Efficient synthesis of 2- and 3-substituted indenes from 2-bromobenzyl bromide through an enolate alkylation/Cr(II)/Ni(II)-mediated carbonyl addition sequence
作者:Ronald L. Halterman、Chengian Zhu
DOI:10.1016/s0040-4039(99)01541-5
日期:1999.10
efficient new synthesis of 2- and 3-substituted indenes has been developed based on the nickel-catalyzed chromium(II)-promoted addition of aryl bromides to a tethered ketone carbonyl. Several tethered bromoaryl ketones were prepared through enolatealkylation of acyclic or cyclic ketones with 2-bromobenzyl bromide. Nozaki-Takai-Hiyama-Kishi closure of the resulting bromoaryl ketones followed by acid promoted
B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>-Catalyzed Highly Stereoselective Hydrogenation of Unfunctionalized Tetrasubstituted Olefins
作者:Yun Dai、Xiangqing Feng、Haifeng Du
DOI:10.1021/acs.orglett.9b02512
日期:2019.9.6
A metal-free hydrogenation of unfunctionalized tetrasubstituted olefins were successfully realized using a combination of B(C6F5)3 and Ph2NMe catalyst. The corresponding products were afforded in 58-98% yields with up to >99:1 cis/trans selectivity.
Hydrogenation reactions with hydridocobalt Tetracarbonyl
作者:Theodore E. Nalesnik、John H. Freudenberger、Milton Orchin
DOI:10.1016/s0022-328x(00)89054-3
日期:1981.12
The tetrasubstituted ethylene, bifluorenylidene, reacts very rapidly (4.06 X 10−2 1 mol−1 sec−1 at 0°C) with HCo(CO)4 to give bifluorenyl. α-Phenylacrylonitrile (atroponitrile) reacts even more rapidly under the same conditions (6.0 l mol−sec−1). Other highly substituted ethylenes react very slowly with HCo(CO)4, indicating considerable steric effects. The data are consistent with radical type intermediates
四取代的乙烯,联芴基,与HCo(CO)4非常迅速地反应(0°C时为4.06 X 10 -2 1 mol -1 sec -1),得到联芴基。在相同的条件下(6.0 l mol - sec -1),α-苯基丙烯腈(a腈)的反应甚至更快。其他高度取代的乙烯与HCo(CO)4的反应非常缓慢,表明存在很大的空间效应。数据与自由基型中间体一致。