Catalytic Desymmetrization of Cyclohexadienes by Asymmetric Bromolactonization
作者:Kazutada Ikeuchi、Shunsuke Ido、Satoshi Yoshimura、Tomohiro Asakawa、Makoto Inai、Yoshitaka Hamashima、Toshiyuki Kan
DOI:10.1021/ol302908a
日期:2012.12.7
Asymmetric bromolactonization of prochiral cyclohexadiene derivatives with N-bromosuccimide proceeded in the presence of (DHQD)(2)PHAL as a chiral catalyst to afford the corresponding bromolactones with up to 93% ee. This reaction was also applicable to the kinetic resolution of a racemic cyclic ene-carboxylic acid, where the starting material was recovered with high enantioselectivity.
Catalytic asymmetric bromolactonization reactions using (DHQD)2PHAL-benzoic acid combinations
作者:Alan Armstrong、D. Christopher Braddock、Alexander X. Jones、Stacy Clark
DOI:10.1016/j.tetlet.2013.10.043
日期:2013.12
Catalytic (DHQD)2PHAL as modified by added benzoic acid, is an off-the-shelf catalyst-additive combination for effecting catalytic asymmetric bromolactonization reactions. This combination delivers bromolactones with asymmetric induction at a comparable level to bespoke catalysts previously optimized for particular substrate classes.