The Mitsunobu reaction [1][2][3][4] is widely employed in both condensation and displacement reactions of alcohols with various nucleophiles and normally proceeds with inversion of stereochemistry when chiral secondary alcohols are used. The mechanism of the reaction continues to receive attention and the present view is summarized in Scheme 1. Although the [*] Dr.

A new class of trialkylphosphorane has been prepared through reaction of a trialkylphosphine with 2-chlorodimethylmalonate in the presence of triethylamine. These new reagents promote the condensation reaction of carboxylic acids with alcohols to provide esters along with trialkylphosphine oxide and dimethylmalonate. The condensation reaction of chiral secondary alcohols can be controlled to give either high levels of inversion or retention through a subtle interplay involving basicity of the reaction media, solvent, and tuning the electronic and steric nature of the carboxylic acid and steric nature of the phosphorane employed. A coherent mechanism is postulated to explain these observations involving reaction via an initial acyloxyphosphonium ion.

The Mitsunobu reaction [1][2][3][4] is widely employed in both condensation and displacement reactions of alcohols with various nucleophiles and normally proceeds with inversion of stereochemistry when chiral secondary alcohols are used. The mechanism of the reaction continues to receive attention and the present view is summarized in Scheme 1. Although the [*] Dr.

Alcohols. -Dimethylmalonyltrialkylphosphoranes are found to be efficient promoters for the condensation of carboxylic acids with alcohols. The reaction with chiral secondary alcohols leads to esters with retention or inversion of configuration depending on solvent, steric and electronic nature of acid, and steric nature of phosphorane. -(MCNULTY*, J.; CAPRETTA, A.; LARITCHEV, V.; DYCK, J.; ROBERTSON, A. J.; J. Org. Chem. 68 (2003) 4, 1597-1600; Dep. Chem., Brock Univ., St. Catharines, Ont. L2S 3A1, Can.; Eng.) -Jannicke 26-100 2003 Carboxylic acid esters