Chemical studies of the stereochemistry of 2-substituted-1,3,2-dioxaphosphorinan-2-ones

Abstract

The configurations at phosphorus in gluco-pyranoside 4,6-(R)- and (S)-methylphosphonate derivatives are established chemically by their conversion, by sequential addition of PhMgBr and EtMgBr, into (S)- and (R)-ethylmethylphenylphosphine oxides respectively; for the formation of 1,3,2-dioxaphosphorinans by phosphorus dihalide–diol reactions the kinetic preference for the thermodynamically less stable isomers depends on steric interactions in twist ring transition intermediates and the subsequent equilibration depends on the relative stabilities of the chair conformers.