title: Highly enantioselective and regioselective copper-catalyzed 1,4 addition of grignard reagents to cyclic enynones.
abstract: In this letter we describe an unusual result in terms of regioselectivity with respect to copper-catalyzed conjugate additions of various Grignard reagents to cyclic enynones. The use of Cu(OTf)(2) and NHC ligand L1 as the catalyst combination in CH(2)Cl(2) led to the unique formation of the 1,4 adduct. This selectivity does not follow the general trend previously observed in the literature using extended Michael acceptors. Moreover these reactions allowed for the creation of a quarternary stereogenic center with enantioselectivities up to 97% ee.
authors.affiliation: Université de Genève, Département de Chimie Organique, 30 Quai Ernest Ansermet, 1211 Genève 4, Switzerland.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Tissot
authors.forename: Alexandra
authors.initials: A
authors.lastname: Pérez Hernández
authors.forename: Daniel
authors.initials: D
authors.lastname: Müller
authors.forename: Marc
authors.initials: M
authors.lastname: Mauduit
authors.forename: Alexandre
authors.initials: A
authors.lastname: Alexakis