Titanocene(II)-promoted multicomponent reactions utilizing alkynyl sulfones, alkenyl sulfones, and carbonyl compounds: a novel method for the synthesis of vinylallenes.
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.
Ogata
Akitoshi
A
Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan.
Nemoto
Masami
M
Kobayashi
Kenji
K
Tsubouchi
Akira
A
Takeda
Takeshi
T