title: Ruthenium-catalyzed enyne cycloisomerizations. Effect of allylic silyl ether on regioselectivity.
abstract: The ruthenium-catalyzed cycloisomerization of 1,6- and 1,7-enynes substituted in the terminal allylic position with a tert-butyldimethylsilyl ether group emerges as an effective reaction to form unprecedented five- or six-membered rings possessing a geometrically defined enol silane. Straightforward synthetic access to a variety of achiral 1,6- and 1,7-enynes, as well as chiral ones, is presented. Ruthenium catalysts effect efficiently such single-step cycloisomerization at room temperature in acetone under neutral conditions. The cycloisomerization functions with (E) or (Z) 1,2-disubstituted alkenes. Parameters influencing the enol silane geometry are discussed. The level of selectivity depends on the alkyne substitution, the geometry of the double bond, and the nature of the catalyst. Furthermore, examples of stereoinduction are shown and lead to highly substituted carbo- and heterocycles with excellent diastereocontrol.
authors.affiliation: Department of Chemistry, Stanford University, Stanford, CA 94305-5080, USA. bmtrost@stanford.edu
authors.forename: Barry M
authors.initials: BM
authors.lastname: Trost
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Surivet
authors.forename: F Dean
authors.initials: FD
authors.lastname: Toste
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D000480:Alkynes / Q000737:chemistry*; D000498:Allyl Compounds / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D004987:Ethers / Q000737:chemistry*; D006844:Hydrocarbons, Cyclic / Q000138:chemical synthesis*; D007536:Isomerism; D012428:Ruthenium / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry*
chemical_list: D000475:Alkenes; D000480:Alkynes; D000498:Allyl Compounds; D004987:Ethers; D006844:Hydrocarbons, Cyclic; D012821:Silanes; D012428:Ruthenium