title: Pd-catalyzed asymmetric allylic substitution reactions using P-chirogenic diaminophosphine oxides: DIAPHOXs.
abstract: 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.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Chiba University, Chiba 263-8522, Japan.
authors.forename: Tetsuhiro
authors.initials: T
authors.lastname: Nemoto
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Hamada
mesh_terms: D000478:Alkylation; D001224:Aspartic Acid / Q000737:chemistry; D002384:Catalysis; D007202:Indicators and Reagents; D008697:Methane / Q000031:analogs & derivatives / Q000737:chemistry; D008968:Molecular Conformation; D009595:Nitroparaffins / Q000737:chemistry; D010087:Oxides / Q000737:chemistry; D010165:Palladium / Q000737:chemistry*; D010720:Phosphines / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D007202:Indicators and Reagents; D009595:Nitroparaffins; D010087:Oxides; D010720:Phosphines; D001224:Aspartic Acid; D010165:Palladium; D008697:Methane; C008640:nitromethane