New chiral β-phosphinocarboxylic acids and their application in palladium-catalysed asymmetric allylic alkylations
Abstract
Chiral β-phosphinocarboxylic acids, conveniently available by conjugate addition of lithium diarylphosphides to α,β-unsaturated carboxylic esters from the chiral pool, show excellent potential as ligands in asymmetric catalysis; in Pd-catalysed allylic substitutions extremely high enantiomeric excess (up to > 99% e.e.) is achieved with cyclic substrates.