Reduction process
United States Patent Moore Apr. 29, 1975 [5 REDUCTION PROCESS 3.799.341 3/1974 Marsheck et al. 195/30 [75] Inventor: Ronald Haywood Moore,  
 M cl fi ld England :rimary Egaminer-filvm Ttzlmenholgtz b &amp;  
  Homer, em, or zrmus man, an [73] Assignee: Imperial Chemical Industries c g y Limited, London, England [22] Filed: Dec. 26, 1973 57 ABSTRACT PP Flo-54281313 The disclosure relates to a steroselective microbiological reduction, for example using Trechispora brink- [30] Foreign Application Priority Data lwzf f la) 0:1 opticaflly active yg fi gg prostag an 1n mterme lates, or exampe a Jan. 15, 1973 United Klngdom 203l/73 p y) y l 2,3,3a,6a-tetrahydro-5-hydroxy-2-oxocyclopenteno[b- 195/51 g igjgg ]furan, to give the optically active form of a known hydroxy enol prostaglandin intermediate for example [58] Field of Search 195/51 R, 30, 29 (3aR,4R5R,6aS) 4 [(3R) 4 (3 chlomphenoxy) 3 [56] References Cited hydroxybut-l-trans-envl]-2,3,3a,6a-tetrahydro-5- UNITED STATES PATENTS hydroxy-Z-oxocyclopenteno[b]furan. $595,902 7/1971 Bcllct m 111 195/51 R 9 Claims Drawings REDUCTION PROCESS This invention relates to a reduction process, and in particular it relates to a microbiological reduction process for the manufacture of intermediates for optically active prostaglandins and prostaglandin-like compounds, having the same configuration at C-l5 as the naturally occurring prostaglandins.  
  According to the invention there is provided a reduction process for the manufacture of an optically active prostaglandin intermediate of the formula and absolute sterochemistry.  
 wherein R is:  
  a branched or unbranched alkyl or alkenyl radical of 4 to 10 carbon atoms; a radical of the formula A. R wherein A is an alkylene radical of l to 9 carbon atoms and R is an alkyl radical of 1 to 9 carbon atoms or a cycloalkyl radical of 5 to 7 carbon atoms, provided that A and P together contain not more than carbon atoms: a radical of the formula A R, wherein A is a direct bond or an alkylene radical of 1 to 3 carbon atoms, and R is an aryl radical which is unsubstituted or which is substituted by halogen atoms, nitro radicals, alkyl, halogenoalkyl, or alkoxy radicals each of l to 3 carbon atoms or dialkylamino radicals wherein each alkyl is of l to 3 carbon atoms; a radical of the formula -A.A. R wherein A is an alkylene radical of l to 3 carbon atoms bearing as substituents 0, l or 2 alkyl radicals each of l to 3 carbon atoms, A is an oxygen or sulphur atom, a sulphinyl radical or an alkylamino radical of up to 4 carbon atoms, and R is an aryl, benzyl or furfuryl radical optionally substituted by hydroxy, nitro or phenyl radicals, halogen atoms, alkyl, alkenyl, halogenoalkyl, alkoxy, alkenyloxy, or acylamino radicals of l to 4 carbon atoms or dialkylamino wherein each alkyl is of l to 3 carbon atoms; or a radical of the formula -A .A .R wherein A has the meaning stated above, A is an oxygen or sulphur atom, a sulphinyl, sulphonyl, imino or alkylamino radical of up to 4 carbon atoms or a direct bond, or A and A are each a direct bond, and R is an aromatic heterocyclic radical of one or two 5- or 6- membered rings, containing in one ring only, 1 or 2 nonadjacent nitrogen hetero-atoms, and optionally bearing 1 to 3 alkyl radicals or halogen atoms as substituents;  
 and either R is a hydrogen atom and R and R together with the two adjacent ring carbon, atoms form a lactone ring of the formula:  
 wherein R, R R and R have the meanings stated above, and R is a hydrogen atom or an alkanoyl radical of up to lOcarbon atoms.  
  A suitable basidiomvcete of the order Aphyllophorales is one belonging to the family Thelephoraceae, or more particularly one of the genus Trechispoa, which is known alternatively as Sistotrema. Particular members of the genus Trechispora or Sistotrema which may be used in the process of the invention are:  
 &#39;I&#39;n&#39;t&#39;hixpuru hrinkmanniitBresadola)Rogcrs and Jackson C M1 T.nireu-&#39;remeu(Hiihncl and Litsch)Boidin CBS 427,54 do. CBS 428.54  
 T. raduloidc.r(Karst.)Rogcrs CBS 163,65  
 Sixmlremu brinkmumiiflBrcsadola)J.Erikss C BS 727.69 do. CBS 154,38 do. CBS 340,53 do. CBS 341,53 do. CBS 401,54 do. CBS 402,54 do. CBS 160.60 do. CBS 932.70  
 S.uhlungis mrum C hristianscn and Hauerslcy CBS 397,63  
  The organisms listed above are particularly useful in a process for the manufacture of a prostaglandin intermediate of the formula I, wherein R is an alkyl radical of 4 to 10 carbon atoms, particularly a n-pentyl or nheptyl radical, or a radical of the formula A.A .R wherein A is a methylene radical, A is an oxygen atom and R is an aryl radical, particularly a 3-chlorophenyl or 3-trifluoromethylphenyl radical, R is a hydrogen atom, P and R, together with the two adjacent ring carbon atoms form a lactone ring of the formula:  
 and R is a hydrogen atom.  
  Theorganism T.brinkmannii has also been described under the name Plrvmalotrichum omnivorum.  
  A suitable basidiomycete of the order Agaricales is one belonging to the family Agaricaceae, or more particularly one of the genus Lentinellus or the genus Armillariella. Particular organisms of the family Agaricaceae are:  
 Lentinellus munranur (O.K.Millcr) Armilluriulla mellcu (Vahlex Fries) Quelct CBS 727.68 lMl 180.725  
  L.mntanus and A.mellea are particularly useful in a process of the invention wherein in the starting material of the formula II, R is an alkyl radical, particularly a n-phenyl or n-heptyl radical, R is a hydrogen atom, R and R together with the two adjacent ring carbon atoms form a lactone ring of the formula:  
 crymycetales is one belonging to the family Dacrymycetaceae or more particularly one of the genus Femsjonia. A particular preferred organism of this group is:  
 Fcmxjunia luleo-ulhu Fr. CBS 209.48  
  A suitable deuteromvce of the order Hyphomvcetales is one belonging to the family Dematicacae or more particularly, one of the genus Helicomyces or Ceratosporella. Particular preferred organisms of this group are:  
  CBS 283.51 CBS l36.58  
  A suitable deuteromycete of the order Cryptococcales is one belonging to the family Cryptococcaceae or more particularly one of the genus Brettanomyces. A particular preferred organism of this group is:&#34;  
 Brelumomwox hru.\z&#39;llt&#39;nsi.r( Kuff and v.Laer) CBS 78 F. Ilito-filba, H. roseus, C. goidanichii and B.bruxel- IensiS are particularly useful in a process of the invention using a starting material of the formula II wherein R is a radical A&#34;.A.R as described above in connection with Trechispora (Sistotrema) species, and B.bruxellensis is also useful in a process using a starting material wherein R is an alkyl radical as described above in connection with Trechispora species.  
  All the organisms identified above by a CM! or [M] reference number are freely available from The Commonwealth Mycological Institute, Kew, Surrey, England, and the organisms identified above by CBS reference numbers are freely available from Centraal Bureau Voor Schimmel Cultures, Baarn, Netherlands.  
  The organisms referred to above are classified according to Ainsworth and Bisbys Dictionary of the Fungi&#34; by G. C. Ainsworth, P. W. James and D. L. Hawksworth, 6th Edition, 197 l published by the Commonwealth Mycological Institute.  
  The organism used in the process of the invention may be cultured in conventional manner, using a conventional medium. The organism is preferably cultured in a submerged suspension in an aqueous medium which includes a carbon source, for example dextrose monohydrate at 0.1 to 5% w/v, a nitrogen source, for example ammonium tartrate at 0.1 to 1.0% w/v and/or yeast extract at 0.02 to 0.3% w/v, a magnesium source, for example magnesium sulphate heptahydrate at 0.01 to 0.2% w/v, a sulphur source, for example the sulphate referred to above, a phosphorus source, for example potassium dihydrogen phosphate at 0.00l-0.5% w/v, and a potassium source, for example the phosphate referred to above, and traces of salts containing metals, for example salts of iron, for example ferrous sulphate hepta-hydrate (up to 10 p.p.m.). copper, for example copper sulphate pentahydrate (up to 5 ppm), zinc, for example zinc sulphate heptahydrate (up to 10 p.p.m.), manganese, for example manganese sulphate tetrahydrate (up to 5 p.p.m.), and molybdenum, for example potassium molybdate (up to 5 p.p.m.). The fer-. mentation may conveniently be carried out at a temperature between 15 and 35C., preferably 25 to 28C.  
  The hydroxyenone of the formula ll wherein R is hydrogen, and R and R together with the adjacent carbon atoms form a lactone ring, may be obtained by the following sequence of reactions:  
 7-Syn-dirnethoxymethylbicyclo[2,2,1]hept-2-en- 5-one (III) is reduced to the corresponding alcohol IV, which is esterified with phthalic acid to give the hemi-phthalate V. Reaction of the hemi-phthalate V with (-)-amphetamine results in the crystallisation of the optically-active (-)-amphetamine salt which is hydrolysed to the optically-active hemiphthalate Vl (All subsequent intermediates in this sequence are of course optically active). The hemiphthalate V1 is hydrolysed to the alcohol VII, which is oxidised with Jones reagent to the ketone VllLBaeyer-Villiger oxidation gives the lactone lX which is rearranged with potassium tri-iodide to the iodohydrin X. The iodohydrin X is protected as the 4-phenylbenzoate ester Xl (R 4- phenylbenzoyl&#39;), and the iodine is removed with tributyl tin hydride to give the de-iodinated lactone Xll which is hydrolysed to the aldehyde XI&#34;. The aldehyde XIII is reacted with a phosphonate reagent of the formula (CH;,O) PO.CH COR in the presence of a strong base to give the protected enone XIV which is then reduced to the protected enol XV. The protecting 4-phenylbenzoyl group is removed by hydrolysis, and the resulting diol XVI is oxidised with manganese dioxide to the required hydroxy-enone starting material 11.  
  The hydroxyenone of the formula II wherein R is a o-carboxyhexyl of 6-carboxy-2-cis-hexenyl radical as defined above, may be obtained from the mixed C-15 epimers of the required prostaglandin and prostaglandin XIV xv moum 1:1 I  
 XVI  
  like compond by oxidation thereof, for example with 2,3-dichloro-5,6-dicyano-l ,4-benzoquinone.  
  The invention is illustrated but not limited by the following Examples:  
 EXAMPLE 1 An agar slant of 45 ml. of nutrient medium was prepared comprising:  
  Potato extract (from 200g. peeled and chopped potatoes boiled in 1 l. of deionised water for minutes, then strained) Dextrose Agar (Oxoid No.3) 7 Deioniscd water 20g. 20g. to l l.  
 and was sterilised for 20 minutes at 15 p.s.i. The medium was inoculated with Trechispora brinkmannii and incubated at C. for 8 days.  
  The whole surface culture of the organism was suspended in 2 ml. of deionised water, and added to a 500 ml. conical flask containing 200 ml; of the following medium:  
 Dextrose monohydrate Ammonium tartratc 2g. Yeast extract lg. KH PO MgSO 7H O 045g- Feso,.&#39;/H,o -O cuso..5H 0 015mgznso,.7H 0 10mg- Mnso,.4H o K MoO t Deionised water to l l.  
 Adjusted to pH 5.5 with ,lONsodium hydroxide, and  
 51a. of an mg./ml. solution in ethanol, and the tube was agitated on a rotary shaker (200 cycles/minute, 0.75 inch radius) at 25C. for&#39;20 hours. The culture was then adjusted to a pH of about 2.5 by addition of 05ml. of a 20% solution of citric acid in water, and the whole mixture was extracted with ethyl acetate (1ml.). The solution contained (3aR, 4R, 5R, 6aS)-2,3,3a, 6atetrahydro-5-hydroxy-4-[(3S)-3-hydroxydec-l -transenyl]-2-oxocyclopenteno[b] furan, identical except for optical activity with authentic racemic material by the following criteria:  
 a. thin&#39;layer chromatography. A sample of p]. of the ethyl acetate solution was applied to a 0.25mm layer of Kieselgel-F254, and the plate was&#39;developed with ethyl acetate. Comparison with authentic racemic material demonstrated the same R; value (0.19), and the same colour reaction on spraying the plate with a solution of vanillin (lg.) in.= 100 ml. of a mixture of equal parts of ethanol, water and phosphoric acid (s.g. 1.75), and subsequent heating;  
 b. .vapour phase chromatography. The remaining ethyl acetate solution was applied to a similar silica gel plate as a 5cm. wide band, and the plate was developed as in (a) above. The band corresponding to the product was removed from the plate, and the product eluted therefrom with methanol. The eluate was evaporated to dryness and the residue was dissolved in ethyl acetate (0.5ml.). A 200/Li. sample of this solution was evaporated to dryness, and the residue was treated with bis-triethylsilyltrifluoroacetamide containing 1% of trimethylchlorosilane, to give the bistrimethylsilyl derivative. This derivative was shown to be identical except for optical activity with the bis-trimethylsilyl derivative of authentic racemic material by:  
 i. identical-retention times of 10.4 minutes on a 5ft.  
  column of 2% methyl vinyl silicone SE-33 supported on Gaschrom A&#34; &#39;(85-100 mesh) at an oven temperature of 220C. and a nitrogen flow rate of&#39;about 50 ml/minute.  
 ii. identical retention times of 7.4 minutes on a ft.  
 long column of 2% methyl silicone OV-l supported on Gas Chrom Q (80-100 mesh) at an oven temperature of 220C. at a helium flow rate of 30 ml./minute;  
 c. mass spectrum. The mass spectrum of the peak from the OV-l column was identical with that of authentic racemic bis-trimethylsilyl derivative EXAMPLE 2 The reduction in Example 1 was carried out with Breltanomyces bruxellensis following the procedure described in Example 1 except that the agar slant consisted of nutrient medium comprising:  
 Malt 20g. Yeast extract 0.1g. Agar (Oxoid No.3) 20g.  
 Dcioniscd water EXAMPLE 3 An agar slant prepared as in Example 2 was inoculated with Lentinellus monranus and incubated at 25C. for 12 days.  
  The whole surface culture of the organism was suspended in ml of the dextrose and ammonium tartrate containing medium described in Example I, and 2ml. of this suspension was transferred to a sterile 4 X inch test-tube. The tube was agitated on a rotary shaker (200 cycles/minute, 0.75 inch radius) at 25C. for 48 hours. (3aR, 4R. 5R, 6aS)-2,3,3a, 6a-tetrahydro-5- hydroxy-2-oxo-4-( 3-oxodecl transenyl)cyclopentenolb] furan (l00p.g.) was added as 0.1m]. ofa lmg./ml. solution in a mixture of ethanol (1 volume) and 0.5% aqueous *Tween (4 volumes), and the tube was agitated for a further 48 hours.-  
  trate pre pared by dipping the plate-in a 5% solution of&#39; silv e r nitrate in a mixture of ethanol 4 volumes) and water (1 volume), and. the plate was developed twice with ethyl acetate. Comparison with authentic racemic material demonstrated the same R value (0.27) and the same colour reaction on spraying the plate with a solution ofrceric sulphate 3g) ii&#39;h l00ml. of 3N-sulphuric acid, and subsequent heating. r  
 b. Vapour phase chromatography. A portion of the ethyl acetate extract was evaporated to dryness and the trimethylsilyl derivative was prepared as in Example I. This was identical except for optical activity with authentic racemic material by vapour phase chromatography on the systems described in I Example l.  
 0. Mass Spectrum. The mass spectrum of the peak from the OV-lcolumn was identical with that of authentic racemic bis-trimethysilyl derivative (M 440) as obtained in Example 1.  
 EXAMPLE 4 The process described in Example 3 was repeated, using Armillariella mellea in place of L.montanus, except that the enone starting material (400ug.) was added as 5p.l. of an mg./ml. solution in ethanol, and that the test tube culture was extracted twice with ethyl acetate (lml.). The combined extract was evaporated to dryness and redissolved in ethyl acetate (lml.). The solution was shown to contain (3aR, 4R, 5P, 6aS)- 2,3,3a, 6a-tetrahydro-5-hydroxy-4-[(3S)-3- hydroxydecl -trans-ethyl1-2-oxocyclopenteno[b]furan, identical except for optical activity with authentic racemic material, as shown by thin layer chromatography of lOOul. aliquots on 0.25mm. layers of Kieselgel- F254, and on Kieselgel-F254 impregnated with silver nitrate, as described in Example 3. Plates were run three times in ethyl acetate and sprayed with ceric sulphate as in Example 3.  
 EXAMPLE 5 A culture of Trechispora brinkmannii in a 500ml. conical flask was prepared as described in Example 1. The culture was shaken at 25C. for 17 days. Mycelium from a 20ml. aliquot was then transferred to a l00ml. conical flask containing (3aR, 4R, 5R, 6aS).-4-[4-(3- chlorophenoxy)-3-oxobut-1-trans-enyl]-2,3,3a, 6atetrahydro-5-hydroxy-2-oxocyclopenteno[b]furan (2mg) and the whole wasresuspended in 20 ml. of the same nutrient medium. The flask was shaken in the same manner for hours. The whole culture was then extracted twice with an equal volume of ethyl acetate. The combined extracts were shown to contain (3aR, 4R, 5R, 6aS)-4-[(3R)-4-(3-chlorophenoxy)-3- hydroxybut-l-trans-enyl]-2,3,3a,6a-tetrahydro-5- hydroxy-Z-oxocyclopenteno[blfuran, identical except for optical activity with authentic racemic material by the following criteria:  
 a. thin layer chrommatography. Samples (400p.L) contained material identical in R; value and colour reaction when applied to a 0.25 mm. layer of Kieselgel F254, and the plate run three times in ethyl acetate and sprayed with vanillin reagent (Example 1 and when applied to a 0.25mm. layer of Kieselgel-F254 impregnated with silver nitrate by dipping in a 10%. solution of silver nitrate in ethanol (4 volumes) andwater (lvolume), the plate run three times in ethyl acetate and sprayed with ceric sulphate reagent (Example 3);  
 b. vapour phase chromatography. A 200p.l. sample was evaporated to dryness and the trimethylsilyl derivative was prepared as described in Example 1. The sample was shown to be identical with the bistrimethylsilyl derivative of authentic racemic material by:  
 i. identical retention tie of 15 minutes on a 5ft. long column of 2% methyl vinyl silicone SE-33 supported on Gas Chrom A (85-100 mesh) at an oven temperature of 230C. and a nitrogen flow rate of about 50ml./minute.  
 ii. identical retention time of 15.6 minutes on a ft. long column of 2% methyl silicone OV-l supported on Gas Chrom Q (80-100 mesh) at an oven temperature of 220C. and a helium flow rate of 30ml./minute;  
 0. mass spectrum. The mass spectrum of the peak from the OV-l column was identical with that of authentic racemic bis-trimethylsilyl derivatives (M 482).  
 EXAMPLE 6 The process described in Example 5 was repeated, using Armillariella mellea in place of T. brinkannii, except that the enone starting material (400 pg.) was added as 11. of a 40mg./ml. solution in ethanol. The product obtained was identical except for optical activity with authentic racemic material by the criteria described in Example 5.  
 EXAMPLE 7 The process described in Example 5 was repeated, using Sistotrema brinkmannii (CBS 727,69) in place of T.brinkmannii. A malt agar slant, prepared as described in Example 2, was inoculated and incubated for approximately days. The whole surface culture was suspended in 10ml. of the dextrose ammonium tartrate medium described in Example 1, and 2m]. were transferred to a test tube as described in Example 3. After 3 days, (3aR, 4R, 5R, 6aS)-4-[4-(3-chlorophenoxy)-3- oxobut-l-transenyl]-2,3,3a,6a-tetrahydro-S-hydroxy- 2-oxocyclopenteno[b]furan (200p.g.) was added as 01ml. of a 2mg./ml. solution in a mixture of ethanol (2 volumes) and 0.5% aqueous solution of Tween (trade mark), (3.4 volumes). The tube was agitated for a further 3 days. The culture was then extracted with ethyl acetate (lml.). The solution contained (3aR, 4R, 5R, 6aS)-4-[( 3R)-4-(3-chlorophenoxy)-3-hydroxybutl-trans-enyl]-2,3,3a, 6a -tetrahydro-5-hydroxy-2- oxocyclopenteno[b]furan, identical except for optical activity with authentic racemic material by the following criteria: I  
 a. thin layer chromatography of 100 1.1. samples on Kieselgel-F254, and on silver nitrate impregnated Kieselgel-F254 as described in Example 5; b. vapour phase chroatography of the trimethylsilyl derivative of a l00p.l. sample, prepared as de- &#34;scribed in Example 1, and chromatographed on the SE-33 column described in Example 5.  
 EXAMPLE 8 The process described in Example was repeated five times, using respectively Helicomvces roseus, Sistotrema brinkmannii strains CBS l5 4&#39;,3 8 ,iCBS 341,53, and CBS 932,70, and Sistotrema oblongisporum, except that the enone starting material (200ug.) was added as 01ml. of a 2mg./ml. solution in ethanol (2 volumes) and 0,5% aqueous .Tween 20 (2.6 volumes) after 2 days incubation of the test-tube cultures, and the cultures were extracted after a further 2 days. The extracts contained (3aR, 4R, 5R, 6a S)-4 [(3R)-4-(3- chlorophenoxy)-3-hydroxybut-1-trans-enyl]-2,3,3a, 6a-tetrahydro-5-hydroxy-2-oxocyclopenteno[blfuran, as shown by the criteria of Example 7, exceptthat 200p.l. samples were applied to the silver nitrate impregnated KieselgelF254 plates.  
  The surface cultures of S.brinkmanni CBS 154,38 and CBS 341,53 were grown on the potato-dextrose agar described in Example 1; S.brinkmannii CBS 932,70 and S.oblongisporum were grown on the melt agar described in Example 2; Helicomyces roseus was grown on an agar slant comprising:  
 Sucrose 30g. NaNO 3g. K HPO, lg. MgSO 7H O 0.5g. KCl 0.5g. Cornstecp liquor 10g. FcSO .7H O 1.0mg. CuSO .5H O 0.15mg. ZnSO .7H O 1.0mg. MnSO .4H O 0. 1 mg. K MoO 0.1mg. Agar 15g.  
 Dcionised water to l 1.  
  Adjusted to pH 7 with sodium hydroxide solution before sterilisation.  
 EXAMPLE 9 The process described in Example 8 was repeated three times, using respectively Sistotrema brinkmannii strains CBS 340,53; CBS 160,60; and CBS 401,54; except that the enone starting material was added as 01ml. of a 2mg./m1. solution in ethanol (1 volume) and 0.5% aqueous Tween 20 (4 volumes).  
  The extracts contained (3aR, 4R, 5R, 6aS)-4-[(3R)- 4-( 3-chlorophenoxy)-3-hydroxybut-1-trans-enyl]- 2,3,3 :1, 6a-tetrahydro-5-hydroxy-2-oxocyclopenteno[b]furan, shown by the same criteria as described in Example 8f The surface cultures used were grown on the potatodextrose agar described in Example 1.  
 EXAMPLE 10 The process described in Example 7 was repeated three times using respectively Brettanomyces bruxellensis, Femsjonia lureo-alba, and Sisrotrema brinkannii (CBS 402,54) as described, except that enone starting material (250 ug.) was added as 50,1.1. of a 5mg./ml. solution in ethanol, and the cultures were extracted twice with ethyl acetate (lml.).  
  The extracts contained (3aR, 4R, 5R, 6aS)-4-[(3R)- 4-3-(ch1orophenoxy)-3-hydroxybut-l-trans-enyl]- 2,3,3a, 6a-tetrahydro-5-hydroxy-2-oxocyclopenteno b]furan, as shown by the criteria described in Example 7, except that 200,ul. samples were applied to Kieselgel-F254 plates, and 30011.1. were applied to KieselgeI-F254 plates impregnated with silver nitrate prepared as described in Example 5; and 200p.1. samples were used for preparation of trimethylsilyl derivatives for vapour phase chromatography.  
 EXAMPLE ll The process described in Example 8 was repeated four times, using respectively Trechispora niveo-crema (CBS 427,54 and CBS 428,54) Trechisopora raduloides andCeratosfiorella goidanichii as described, except that the enone starting&#39;material was added as described in Example 9.  
  The product extract contained (3aR, 4R, 5R, 6aS)-4- [(3R)-4-(3-chlorophen0xy)-3-hydroxybut-l-tra&#39;nsenyl]-2,3,3a, 6a-tetrahydro-5-hydroxy-2-oxocyclopenteno[b]furan, as shown by the criteria thatit&#39;was identical to authentic racemic aterial on thin layer chromatography of a p.l. sample on a Kieselgel-F254 plate 13 run three times in ethyl acetate and sprayedwit h the vanillin reagent; (Example I), and on vapour phase&#39; chromatography as the bis-trimethylsil yl derivative on the SE-33column as described in Example 5.  
 EXAMPLE 12 The process described in Example was repeated using (3aR, 4R, 5R. 6aS)-2,3,3a, 6a-tetrahydro-5 hydroxy-2-oxo-4-[ 3-oxo-4-( 3- Y trifluoromethylphenoxy)but-l-trans-enyllcyclopentenolblfuran in place of (3aR, 4R, 5R, 6aS)-4-[4-(3- chlorophenoxy)-3-hydroxybut-l-trans-enyl]-2,3,3a, oa-tetrahydro-S-hydroxy-2-oxocyclopenteno [b]furan. The extract obtained was shown to contain (3aR, 4R, 5R, 6aS)-2.3,3a, 6a-tetrahydro-5-hydroxy-4-[(3R)-3- hydroxy-4-(3-trifluoroemthylphenoxy)but1trans-enyl]- 2oxocyclopenteno[blfuran, identical except for optical activity with authentic material by the following criteria: .3  
 a. thin layer chromatography as described in Example 5 b. vapour phase chromatography described in Example 5, the bis-trimethy] silyl derivative having retention time of 7.6 minutes on the SE 33 column and 7.9 minutes on the OV-lcolumn.  
 y c. mass spectrum. The mass spectrum ofthe peak from the OV-l column was identical with that of authentic racemic bis-trimethylsilyl derivative (M 516) EXAMPLE 13 The process described in Example 12 was repeated using each of the cultures, and the procedure, described in Example 10. In each case, the product was shown to contain material identical with authentic racemic 2,3,3aB,6aB-tetrahydro-5a-hydroxy-4B-[3- trifluoromethylphenoxy)but-l-trans-enylLZ-oxocyclopenteno[b]furan by:  
 a. thin layer chromatography of a (),ul. sample on a Kieselgel-F254 plate, and a 300a]. sample on a Kieselgel-F254 plate impregnated with silver nitrate as described in Example 5, the plates being run three times in ethyl acetate and sprayed with the eerie sulphate reagent (Example 3); b. vapour phase chromatography of the bistrimethylsilyl derivative, prepared from a 200 11. sample, on the SE 33 column described in Example 5. What we claim is: l. A reduction process for the manufacture of an optically active prostaglandin intermediate of the formula and absolute sterochemistry:  
 wherein R is:  
 branched or unbranched alkyl or alkenyl of 4 to 10 carbon atoms; a group of the formula A.OR wherein A is alkylene of l to 9 carbon atoms and R is alkyl of l to 9 carbon atoms or cycloalkyl of 5 to 7 carbon atoms, provided that A and R to gether contain not more than l0 carbon atoms;  
 a group of the formula -A R, wherein A is a direct bond or alkylene of 1 m3 carbon atoms, and R is aryl which is unsubstituted or which is substituted by halogen, nitro, alkyLhalogenoalkyl, or alkoxy each of l to 3 carbon atoms or dialkylamino wherein each alkyl is of l to 3 carbon atoms;  
 a group of the formula A.A.R wherein A is alkylene of l to 3 carbon atoms bearing as substituents 0, 1 or .2 alkyls eachof l to 3 carbon atoms, A is oxygen, sulphur, sulphinyl or alkylamino of up to 4 carbon atoms, and R is aryl, benzyl or furfuryl optionally substituted by hydroxy, nitro, phenyl, halogen, alkyl, alkenyl, halogenoalkyl, alkoxy, alkenyloxy, or acylamino of l to 4 carbon atoms or dialkylamino wherein each alkyl is of l to 3 carbon atoms; or a group of the formula A&#34;.A .R*, wherein A has the meaning stated above, A is oxygen, sulphur, sulphinyl, sulphonyl, imino or alkylimino of up to 4 carbon atoms or a direct bond, A and A are each a direct bond, and R&#34; is an aroatic heterocyclyl of one or two 5- or 6- membered rings, containing in one ring only, 1 or 2 non adjacent nitrogen hetero atoms, and optionally bearing 1 to 3 alkyls or halogens as substituents; and either R is hydrogen and R and R together with the two adjacent ring carbon atoms form a lactone ring of the formula:  
 or R is -carboxyhexyl or 6-carboxy-2-cis-hexcnyl bearing 0 or 1 alkyl of l to 4 carbon atoms on carbon atom 4, 5 or 6 thereof, R is hydrogen and R is hydroxy, or R and R together form oxo;  
 which comprises culturing a micro-organism selected from a basidiomycete of the order Aphyllophorales, Agaricales or Dacrymycetales, a deuteromycete of the order Hyphommycetales and a blastomycete of the order Gryptococcales in the presence of a hydroxy-enone of the formula:  
 wherein R, R R and R have the meanings stated above, and R is a hydrogen atom or alkanoyl of up to 10 carbon atoms.  
  2. The process of claim 1 wherein in the starting material, R is alkyl of4 to 10 carbon atos, R is hydrogen, R and R together with the two adjacent carbon atoms form a lactone ring as defined in claimm l and R&#34; is hydrogen, wherein the micro-organism is selected from a basidiomycete of the genus Trechispora (=Sistotrema) or Lentinellus, or a blastom mycete of the genus Brettanomyces.  
  3. The process of claim 2 wherein in the starting material R is a n-pentyl or n-heptyl radical.  
  4. The process of claim 2 wherein the microorganism is selected from T.brinkmmannii (Bresadola) Rogers and Jackson, strain CMl 80,439, L.mntanus (O.K. Miller), strain CBS 727,68, A.ellea (Vahlex Fries) Quelet, strain 1MM1 180,725 and B. bruxellensis (Kuff and v. Laer), strain CBS 78.  
  5. The process of claim 1 wherein in the starting material, R is a group A.A&#34;.R wherein A is methylene, A is oxygen and R is aryl as defined in claim 1, R is hydrogen, R and R together with the two adjacent carbons form a lactone ring as defined in claim 1, and R is hydrogen, wherein the micro-organism is selected from a basidiomycete of the genus Trechispora (=Sistotrema), Armmillariella or Femsjonia, a deuteromycete of the genus l-lelicomyces or Ceratosporella, and a blastomycete of the genus Brettanommyces.  
  6. The process of claim wherein in the starting material R is 3-chlorophenyl or 3-trifluoromethylphenyl.  
  7. The process of claim 5 wherein the microorganis is selected microorganism T.brinkannii (Bresadola) Rogers and Jackson, strain CMl 80,439, T.nive0-creea (Hohnel and Litsch) Boidin, strains CBS 427,54 and 428,54, T.radul0iies (Karst) Rogers, strain CBS 163,65, Shrinkmannii (Bresadola) J. Erikss, strains CBS 727,69, 154,38, 340,53, 341,53, 401,54, 402,54, 160,60, and 932,70, S.0bl(mgisp0ru Christiansen and Hauerslev, strain CBS 397.63, AJneIlea, strain IMI 180,725, FJuteo-alba Fr.. strain CBS 209,48, H. Rnseus Link, strain CBS 283,51, C. goidanichii Rammbelli, strain CBS 136,58 and B. brzixellensis (Kuff and v. Laer), strain CBS 78.  
  8. The process of claim 3 wherein the microorganism is selected from T.brinkmannii (Bresadola) Rogers and Jackson, strain CMl 80,439, L.montanus (0.K. Miller), strain CBS 727,68, A. Mellea (Vahlex Fries) Qulet, strain 1M1 180,725 and B. bruxellensis (Kuff and v. Laer), strain CBS 78.  
  9. The process of claim 6 wherein the microorganism is selected from T.brinkmannii (Bresadola) Rogers and Jackson, strain CMl 80,439, T.nive0-cremea (Hb&#39;hnel and Litsch) Boidin, strains CBS 427,54 and 428,54, 7. raduloides (Karst) Rogers, strain CBS 163,65, S. brinkmannii (Bresadola) J. Erikss, strains CBS 727,69, 154,38, 340,53, 341,53, 401,54, 402,54, 160,60, and 932,70, S. oblongisporum Cltristiansen and Halterslev, strain CBS 397,63, A.mellea, strain 1M1 180,725, FJuteo-alba Fr., strain CBS 209,48, H. roseus Link, strain CBS 283,51, C.g0idanicnii Rambelli, strain CBS 136,58 and B.bru.\&#39;ellensis (Kuff and v. Laer), strain CBS 78.