An efficient resolution of phosphinous acid-boranes

A general protocol has been developed for the resolution of racemic P-stereogenic phosphinous acid-boranes. It employs cinchonine as the resolving agent and most frequently gives an access to the pertinent diastereomerically pure cinchoninium salt of the acid in a single crystallization step. The resolved acids were assigned their absolute configurations by chemical correlations with already known enantiomerically pure phosphinite-boranes. (c) 2007 Elsevier Ltd. All rights reserved.