A stereochemical study of some reactions of compounds in the 4-methyl-1,3,2-dioxaphosph(V)orinan series

Abstract

Stereochemistries are assigned to the geometrical isomers of the secondary phosphite 4-methyl-2-oxo-1,3,2-dioxaphosphorinan (I) on the basis of n.m.r. and dipole moment measurements. Chlorination of the isomers of (I) leads stereospecifically to isomers of the chloridate (III). Both isomers of (III) react stereospecifically with piperidine to yield the corresponding piperidide. The cis-form undergoes methanolysis with high stereospecificity whereas the trans-form is methanolysed with low stereospecificity. The stereochemistries of some reactions of the chloridite 2-chloro-4-methyl-1,3,2-dioxaphosphorinan (II) and the phosphite 2-methoxy-4-methyl-1,3,2-dioxaphosphorinan are also described. The interconversion and relative stabilities of the isomers of (I) have been examined.