Pd‐catalyzed asymmetric allylic substitution reactions using P‐chirogenic diaminophosphine oxides: DIAPHOXs

This paper describes the development of a new class of chiral phosphorus ligand: aspartic acid‐derived P‐chirogenic diaminophosphine oxides, DIAPHOXs, and their application to several Pd‐catalyzed asymmetric allylic substitution reactions. Pd‐catalyzed asymmetric allylic alkylation was initially examined in detail using diaminophosphine oxides 1a , resulting in the highly enantioselective construction of quaternary stereocenters. Mechanistic investigations revealed that 1a is activated by N,O ‐bis(trimethylsilyl)acetamide‐induced tautomerization to afford a trivalent diamidophosphite species 12 , which functions as the actual ligand. Furthermore, asymmetric allylic amination was examined using Pd‐DIAPHOX catalyst systems, providing a variety of chiral allylic amines. © 2007 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 7: 150–158; 2007: Published online in Wiley InterScience ( www.interscience.wiley.com ) DOI 10.1002/tcr.20108