title: Titanocene(II)-promoted multicomponent reactions utilizing alkynyl sulfones, alkenyl sulfones, and carbonyl compounds: a novel method for the synthesis of vinylallenes.
abstract: Titanocene(II)-promoted cross coupling of alkynyl- and (Z)-alkenyl sulfones affords alpha-(phenylsulfonyl)alkenyltitanium species. Further treatment of these species with the titanocene(II) reagent generates titanium vinylvinylidene complexes, which react with carbonyl compounds in one pot to produce substituted vinylallenes with complete stereoselectivity. By using alpha,beta-unsaturated ketones, 1,3,4,6-tetraenes are also obtained stereoselectively.
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan.
authors.forename: Akitoshi
authors.initials: A
authors.lastname: Ogata
authors.forename: Masami
authors.initials: M
authors.lastname: Nemoto
authors.forename: Kenji
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Akira
authors.initials: A
authors.lastname: Tsubouchi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Takeda