title: Direct conjugate alkylation of α,β-unsaturated carbonyls by Ti(III)-catalysed reductive umpolung of simple activated alkenes.
abstract: The titanium(iii)-catalysed cross-selective reductive umpolung of Michael-acceptors represents a unique direct conjugate β-alkylation reaction. It allows the cross-selective preparation of 1,6- and 1,4-difunctionalised building blocks without the requirement of stoichiometric organometallic reagents. In this full paper, the development and scope of the titanium(iii)-catalysed cross-selective reductive umpolung of Michael-acceptors is described. Based on the observed selectivities and additional mechanistic experiments a refined mechanistic proposal is presented.
authors.affiliation: Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertsraße 21, 79104 Freiburg, Germany. jan.streuff@ocbc.uni-freiburg.de.
authors.forename: Plamen
authors.initials: P
authors.lastname: Bichovski
authors.affiliation: Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertsraße 21, 79104 Freiburg, Germany. jan.streuff@ocbc.uni-freiburg.de.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Haas
authors.affiliation: Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertsraße 21, 79104 Freiburg, Germany. jan.streuff@ocbc.uni-freiburg.de.
authors.forename: Manfred
authors.initials: M
authors.lastname: Keller
authors.affiliation: Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertsraße 21, 79104 Freiburg, Germany. jan.streuff@ocbc.uni-freiburg.de.
authors.forename: Jan
authors.initials: J
authors.lastname: Streuff