The structure of regalamine
SummaryOn the basis of UV, IR, NMR, and mass spectra and chemical transformations the structure of 11,12-dihydroxy-2-methoxy-1,12-epoxyhexahydrohomoproaporphine has been proposed for regalamine.
Enantioselective Total Syntheses of Pentacyclic Homoproaporphine Alkaloids.
Herein we report the first enantioselective total syntheses of pentacyclic homoproaporphine alkaloids by means of a route, which includes a tandem retro-oxa-Michael addition and nucleophilic substitution to generate the oxa-benzobicyclco[3.3.1]nonane core structure, a Pictet-Spengler cyclization to construct the fused B and C rings, and sequential Baeyer-Villiger oxidation and pinacol-type cyclization to install the hydroxyl-lactol moiety of D ring. With this unified route, six pentacyclic homoproaporphine alkaloids have been synthesized enantioselectively.
The absolute configuration of (–)-floramultine, an alkaloid from Kreysigia multiflora Reichb
* Manuscript received July 17, 1968. t Division of Chemical Physics, CSIRO Chemical Research Laboratories, P.O. Box 160, Clayton, Vic. 3168. $ Division of Applied Chemistry, CSIRO Chemical Research Laboratories, P.O. Box 4331, Melbourne, Vic. 3001. Battersby, A. R., Bradbury, R. B., Herbert, R. B., Munro, 31. H. G., and Ramage, R., Chem. Commun., 1967, 450. Badger, G. If . , and Bradbury, R. B., J. chem. Soc., 1940, 446.