A convenient route to the phosphorus and sulfur stereoisomers of ethyl menthyl (methylsulfinyl)methylphosphonate
摘要:
The four phosphorus and sulfur stereoisomers of ethyl menthyl (methylsulfinyl)methylphosphonate were obtained by preparing the corresponding sulfides from commercially available diethyl (methylthio)methylphosphonate and subjecting them to a highly diastereoselective hydroperoxide oxidation in the presence of catalytic amounts of a titanium (R)- or (S)-BINOL complex. The configuration at the sulfur stereogenic centre was assigned by a chemical correlation based upon a displacement reaction with Grignard reagents, whereas the configuration at the phosphorus stereogenic centre was assigned by taking advantage of a reaction sequence based upon the use of menthyl (R-p)-methylphosphonothioic acid as a starting material. (C) 2004 Elsevier Ltd. All rights reserved.