title: Catalytic isomerization of 1,5-enynes to bicyclo[3.1.0]hexenes.
abstract: The cycloisomerization of 1,5-enynes catalyzed by cationic triphenylphosphinegold(I) complexes produces bicyclo[3.1.0]hexenes. Substitution at all positions of the 1,5-enyne is tolerated, leading to a wide range of bicyclo[3.1.0]hexane structures, including those containing quaternary carbons. Substrates containing a 1,2-disubstituted olefin undergo stereospecific cycloisomerization (cis-olefin produces cis-cyclopropane, and trans-olefin gives trans-cyclopropane). Additionally, enantioenriched bicyclo[3.1.0]hexenes can be obtained from the gold(I)-catalyzed cycloisomerization of enantioenriched 1,5-enynes with excellent chirality transfer. The preparation of tricyclic systems is accomplished through a gold(I)-catalyzed tandem cycloisomerization-ring enlargement reaction.
authors.affiliation: Center for New Directions in Organic Synthesis, Department of Chemistry, University of California-Berkeley, Berkeley, CA 94720, USA.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Luzung
authors.forename: Jordan P
authors.initials: JP
authors.lastname: Markham
authors.forename: F Dean
authors.initials: FD
authors.lastname: Toste