Catalytic enantioselective alkylations of tetrasubstituted olefins. Synthesis of all-carbon quaternary stereogenic centers through Cu-catalyzed asymmetric conjugate additions of alkylzinc reagents to enones.
A method for Cu-catalyzed asymmetric conjugate addition (ACA) of dialkylzinc reagents to tetrasubstituted five- and six-membered cyclic enones that afford quaternary all-carbon stereogenic centers in up to 95% ee is reported. Catalytic ACAs are practical and efficient. Reactions proceed to >98% conversion in undistilled commercial grade toluene in the presence of 2 mol % of an air-stable Cu salt (CuCN) and a readily available chiral ligand. Enantioselective ACA reactions deliver products that can be readily functionalized to afford a variety of synthetically versatile compounds in high optical purity.
Hird
Alexander W
AW
Department of Chemistry, Merkert Chemistry Center, Boston College, Massachusetts 02467, USA.
Hoveyda
Amir H
AH
D000473:Alkanes / Q000737:chemistry; D000475:Alkenes / Q000737:chemistry*; D000478:Alkylation; D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D003300:Copper / Q000737:chemistry*; D008956:Models, Chemical; D009942:Organometallic Compounds / Q000138:chemical synthesis*; D013237:Stereoisomerism; D015032:Zinc / Q000737:chemistry*
D000473:Alkanes; D000475:Alkenes; D009942:Organometallic Compounds; D002244:Carbon; D003300:Copper; D015032:Zinc