Copper(I)-Catalyzed Stereo- and Chemoselective Borylative Radical Cyclization of Alkyl Halides Bearing an Alkene Moiety
作者:Hiroaki Iwamoto、Sota Akiyama、Keiichi Hayama、Hajime Ito
DOI:10.1021/acs.orglett.7b00940
日期:2017.5.19
The stereoselective borylative radical cyclization of alkyl halides containing an alkene moiety was developed using a copper(I)/diboron catalyst system. The optimized reaction conditions allowed us to control the chemoselectivity between the allylic substitution and the borylative radical cyclization. The borylation products were subsequently converted to highly functionalized organic compounds by
New methods for reductive free-radical cyclizations of α-bromoacetals to 2-alkoxytetrahydrofurans with activated chromium(II)-acetate
作者:Claus Hackmann、Hans J. Schäfer
DOI:10.1016/s0040-4020(01)81285-0
日期:1993.5
free-radical cyclization of α-bromoacetals 4 to 2-alkoxytetrahydrofurans 5 in 54–93% yield induced by activated chromium(II)-acetate. Four new methods have been developed in order to activate the transition metal. Two of them require only catalytic amounts of chromium(II)-acetate, because it can be regenerated in situ chemically or electrochemically. The diastereoselectivity of the cyclization depends on