title: Enantioselective cyclizations of silyloxyenynes catalyzed by cationic metal phosphine complexes.
abstract: The discovery of complementary methods for enantioselective transition metal-catalyzed cyclization with silyloxyenynes has been accomplished using chiral phosphine ligands. Under palladium catalysis, 1,6-silyloxyenynes bearing a terminal alkyne led to the desired five-membered ring with high enantioselectivities (up to 91% ee). As for reactions under cationic gold catalysis, 1,6- and 1,5-silyloxyenynes bearing an internal alkyne furnished the chiral cyclopentane derivatives with excellent enantiomeric excess (up to 94% ee). Modification of the substrate by incorporating an α,β-unsaturation led to the discovery of a tandem cyclization. Remarkably, using silyloxy-1,3-dien-7-ynes under gold catalysis conditions provided the bicyclic derivatives with excellent diastereo- and enantioselectivities (up to >20:1 dr and 99% ee).
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720, USA.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Brazeau
authors.forename: Suyan
authors.initials: S
authors.lastname: Zhang
authors.forename: Ignacio
authors.initials: I
authors.lastname: Colomer
authors.forename: Britton K
authors.initials: BK
authors.lastname: Corkey
authors.forename: F Dean
authors.initials: FD
authors.lastname: Toste
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D002412:Cations / Q000737:chemistry; D003500:Cyclization; D006046:Gold / Q000737:chemistry*; D015394:Molecular Structure; D017646:Organosilicon Compounds / Q000737:chemistry*; D010720:Phosphines / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000480:Alkynes; D002412:Cations; D017646:Organosilicon Compounds; D010720:Phosphines; D006046:Gold; C044646:phosphine