PREPARATION, ALKYLATION REACTIONS, AND CONFORMATIONAL-ANALYSIS OF ESTERS OF PHOSPHOLANIC ACID - PREPARATION AND REACTIVITY OF (2S-STAR,5S-STAR)-1,2,5-TRIBENZYL-1-OXOPHOSPHOLANE

Optimum conditions for the reaction of 1,4-butanediyldimagnesium dibromide and alkyl phosphorodichloridates are described. The general geometric requirements of the cyclization reaction transition state are discussed. Alkylation reactions of phospholanate esters 2b and 2c are reported. Conformational analysis of various phospholanate esters is discussed in terms of 3J(PC) and 3J(PH) data, NOE experiments, and crystal structures of related phospholane derivatives. trans-2,5-Dibenzyl phosphinate esters 15b and 15c were converted to (2S*,5S*)-1,2,5-tribenzyl-1-oxophospholane 18 by reductive alkylation. Phosphine oxide 18 was shown to participate in an olefination reaction with 4-tert-butylcyclohexanone.