title: Enantioselective synthesis of α-quaternary Mannich adducts by palladium-catalyzed allylic alkylation: total synthesis of (+)-sibirinine.
abstract: A catalytic enantioselective method for the synthesis of α-quaternary Mannich-type products is reported. The two-step sequence of (1) Mannich reaction followed by (2) decarboxylative enantioselective allylic alkylation serves as a novel strategy to in effect access asymmetric Mannich-type products of "thermodynamic" enolates of substrates possessing additional enolizable positions and acidic protons. Palladium-catalyzed decarboxylative allylic alkylation enables the enantioselective synthesis of five-, six-, and seven-membered ketone, lactam, and other heterocyclic systems. The mild reaction conditions are notable given the acidic free N-H groups and high functional group tolerance in each of the substrates. The utility of this method is highlighted in the first total synthesis of (+)-sibirinine.
authors.affiliation: Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Numajiri
authors.forename: Beau P
authors.initials: BP
authors.lastname: Pritchett
authors.forename: Koji
authors.initials: K
authors.lastname: Chiyoda
authors.forename: Brian M
authors.initials: BM
authors.lastname: Stoltz
mesh_terms: D000478:Alkylation; D000498:Allyl Compounds / Q000737:chemistry*; D002384:Catalysis; D003497:Cyclic N-Oxides / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000498:Allyl Compounds; D003497:Cyclic N-Oxides; D009942:Organometallic Compounds; D010165:Palladium