Synthesis of chiral 2-oxo- and 2-thio-1,3,2-oxazaphospholidines via the asymmetric cyclization of l-serinoates with (thio)phosphoryl dichlorides

In this article, we have described the asymmetric cyclization of L-serinoates and N-benzyl L-serinoate with phosphoro(no-)dichloridates or their thio-analog, respectively, and we have investigated the asymmetric induction effect of the chiral carbon center on the forming of a chiral phosphorus center. The diastereomeric excess percentages (de%) of the desired products 2-oxo- and 2-thio-1,3,2-oxazaphospholidines, are obtained based on their ³¹P NMR data. In some cases, the cyclization products have been separated as pure diastereomers by column chromatography. Their configuration is preliminarily discussed. © 2000 John Wiley & Sons, Inc. Heteroatom Chem 11:187–191, 2000