title: Gold(I)-catalyzed enantioselective synthesis of benzopyrans via rearrangement of allylic oxonium intermediates.
abstract: The first transition metal catalyzed asymmetric carboalkoxylation reaction of propargyl esters is described. The (R)-MeO-DTBM-BIPHEP(AuCl)(2)-catalyzed reactions allow for the construction of benzopyrans containing quaternary stereocenters with excellent enantioselectivity. Experimental evidence supports a mechanism proceeding via the generation of a stabilized carbocation from an allylic oxonium intermediate and subsequent trapping by a chiral allylgold(I) spieces.
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720, USA.
authors.forename: Minoru
authors.initials: M
authors.lastname: Uemura
authors.forename: Iain D G
authors.initials: ID
authors.lastname: Watson
authors.forename: Mikimoto
authors.initials: M
authors.lastname: Katsukawa
authors.forename: F Dean
authors.initials: FD
authors.lastname: Toste
mesh_terms: D001578:Benzopyrans / Q000737:chemistry*; D002384:Catalysis; D006046:Gold / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D001578:Benzopyrans; D006046:Gold