title: Contemporaneous dual catalysis: chemoselective cross-coupling of catalytic vanadium-allenoate and π-allylpalladium intermediates.
abstract: This paper presents a detailed investigation of a dual catalytic system that combines a vanadium-catalyzed Meyer-Schuster rearrangement and a palladium-catalyzed allylic alkylation. The implementation of this novel reaction relies on matching the formation rates of vanadium-allenoate and π-allylpalladium intermediates with their bimolecular coupling rate in order to minimize the undesired protonation or O-alkylation of the catalytically generated intermediates. Chemoselectivity in this dual catalytic process was successfully achieved by adjusting ligand structure and catalyst loading ratios of the vanadium and palladium catalysts. A great range of coupling partners for both the propargyl alcohol and allyl carbonate components are readily accommodated in this new transformation, which in turn provides a novel avenue to a variety of α-allylated α,β-unsaturated ketones, esters, and amides in moderate to excellent isolated yields.
authors.affiliation: Department of Chemistry, Stanford University, Stanford, California 94305-5080, United States. bmtrost@stanford.edu
authors.forename: Barry M
authors.initials: BM
authors.lastname: Trost
authors.forename: Xinjun
authors.initials: X
authors.lastname: Luan
authors.forename: Yan
authors.initials: Y
authors.lastname: Miller