title: Chiral cyclopentadienylruthenium sulfoxide catalysts for asymmetric redox bicycloisomerization.
abstract: A full account of our efforts toward an asymmetric redox bicycloisomerization reaction is presented in this article. Cyclopentadienylruthenium (CpRu) complexes containing tethered chiral sulfoxides were synthesized via an oxidative [3 + 2] cycloaddition reaction between an alkyne and an allylruthenium complex. Sulfoxide complex 1 containing a p-anisole moiety on its sulfoxide proved to be the most efficient and selective catalyst for the asymmetric redox bicycloisomerization of 1,6- and 1,7-enynes. This complex was used to synthesize a broad array of [3.1.0] and [4.1.0] bicycles. Sulfonamide- and phosphoramidate-containing products could be deprotected under reducing conditions. Catalysis performed with enantiomerically enriched propargyl alcohols revealed a matched/mismatched effect that was strongly dependent on the nature of the solvent.
authors: Department of Chemistry, Stanford University, Stanford, California 94305-5580, USA.
authors: Barry M
authors: BM
authors: Trost
authors: Department of Chemistry, Stanford University, Stanford, California 94305-5580, USA.
authors: Michael C
authors: MC
authors: Ryan
authors: Department of Chemistry, Stanford University, Stanford, California 94305-5580, USA.
authors: Meera
authors: M
authors: Rao
keywords: 1,6-enyne; 1,7-enyne; [3.1.0] bicycles; [4.1.0] bicycles; asymmetric catalysis; cycloisomerization; ruthenium catalysis; sulfoxide