Synthesis of Functionalized 3-Bromoindenes via Pd(II)-catalyzed Tandem Reactions of <i>o</i>-(Alkynyl)styrenes: Taking Dioxygen as Sole Oxidant
作者:Peng Zhou、Weibing Liu、Huihua Qiu
DOI:10.1246/cl.150756
日期:2015.12.5
This paper introduced an economic and environmental approach to 3-bromoindenes from simple and readily available o-(alkynyl)styrenes via a Pd-catalyzed cascade cyclization including bromopalladation/Heck cross-coupling/β-H elimination. With O2 as the sole oxidant and KBr as bromide source, a series of poly-substituted 3-bromoindenes were synthesized with high chemoselectivity avoiding the use of CuBr2.
Palladium-catalyzed tandem reactions of 2-alkenylphenyl-acetylenes with CuCl2 or CuBr2 afforded 3-chloro- or 3-bromo-1-methyleneindenes in good yields; these compounds could be further elaborated viapalladium-catalyzed coupling reactions.