Fragmentation studies of pentacoordinated bisaminoacylspirophosphoranes by negative electrospray ionization mass spectrometry.
Fragmentation pathways of a series of pentacoordinated bisaminoacylspirophosphoranes were elucidated by electrospray ionization multistage mass spectrometry (ESI-MS(n)) in negative mode. The deprotonated ions of pentacoordinated bisaminoacylspirophosphoranes tend to eliminate a corresponding amino acid to form base peak. The hydrogen/deuterium exchange experiment, the high-resolution mass spectrometry, (13)C stable isotope labeling experiment and theoretical calculations were used to rationalize the proposed fragmentation pathways and to verify the differences between the fragmentation pathways. The results indicate that the negative molecular ions of pentacoordinated bisaminoacylspirophosphoranes dissociate through its open-chain tricoordinated tautomers. The relative Gibbs free energies (ΔG) of the product ions and proposed fragmentation pathways were estimated using the B3LYP/6-31 + + G(d, p) model. The results have some potential applications in the identification structures of similar spirophosphorane compounds by ESI-MS(n).
Propriétés nucléophiles des phosphoranures
The reaction of various bases with P—H bond-containing phosphoranes bearing α-hydroxy acid, α-aminoacid, or iminodiacetic acid ligands leads to the formation of phosphoronates which react with electrophiles such as alkyl halides, phenyl azide, carbon disulfide, orthoquinones, or keto-acids. New phosphoranes and hexacoordinated phosphorus compounds could thus be prepared. [Journal translation]
Reactions de metallation dans la serie des spirophosphoranes a liaison PH. Formation de la liaison PVC
Abstract We report here the generation and reactions of reagents such as A, in which M = Li or Na. The action of various metallation reagents (RLi, R 2 NLi, HNa, NH 2 Na) in THF at room temperature has been tested on 2,2,3,3,7,7,8,8-octamethyl-1,4,6,9-tetraoxy-5-phospha(V)[4.4]spirononane. Only R 2 NLi and NH 2 Na are effective. The metallated intermediate is probably an oxanion rather than a phosphanion. Some coupling reactions of these reagents with various RX and their use in hydroxyspirophosphorane synthesis are described.