title: Highly enantioselective construction of a chiral spirocyclic structure by the [2 + 2 + 2] cycloaddition of diynes and exo-methylene cyclic compounds.
abstract: The enantioselective [2 + 2 + 2] cycloaddition of 1,6-diynes with alpha-methylene lactones and cyclic ketones gave various chiral spirocyclic compounds. The reaction proceeded with high enantioselectivity when the rhodium-xylylBINAP complex was used as a chiral catalyst. Not only exo-methylene cyclic compounds but also exo-methylene acyclic compounds could be used as coupling partners for diynes. The present protocol provides access to a new chiral library possessing a quaternary carbon center, including a spirocyclic system.
authors.affiliation: Department of Chemistry, School of Science and Engineering, Waseda University, Shinjuku, Tokyo, 169-8555, Japan.
authors.forename: Kyoji
authors.initials: K
authors.lastname: Tsuchikama
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kuwata
authors.forename: Takanori
authors.initials: T
authors.lastname: Shibata