71877-77-5Relevant academic research and scientific papers
Chiral Mono-, Di, and Tri-chloromethylphosphonates and Phosphonothioates: Preparation, Absolute Configuration, and the Stereochemical Course of Their Reaction with Methoxide
Hall, C. Richard,Inch, Thomas D.,Peacock, Gary,Pottage, Colin,Williams, Nancy E.
, p. 669 - 674 (2007/10/02)
Enantiomerically pure (+)-(R)-O-ethyl S-methyl dichloromethylphosphonothioate, prepared using (-)-ephedrine as a chiral template, is futher chlorinated to the trichloro analogue using BunLi-CCl4 and dechlorinated by hydrogenolysis via the monochloro analogue to the corresponding methyl-phosphonothioate of known configuration.With methoxide, the trichloro derivatives gives P-C bond cleavage with inversion and the dichloro derivatives gives P-S bond cleavages with retention of configuration.In the monochloroderivative P-S and P-O bond cleavages are competitive, P-S bond cleavage occuring with 70percent inversion.Under similar reaction conditions P-S bond cleavage occurs stereospecifically with inversion of configuration in methylphosphonothioates.Methoxide treatment of (+)-(R)-ethyl isopropyl trichloromethylphosphonate results in P-C bond cleavage with inversion while (-)-(S)-ethyl phenyl dichloromethylphosphonate loses the OPh group also with inversion.Possible reaction mechanisms are discussed.
