A highly efficient (aS)-Ir/In-BiphPHOX-catalyzed asymmetric hydrogenation of substituted 2H-chromenes and substituted benzo[e][1,2]oxathiine 2,2-dioxides is described. A series of 2H-chromenes and benzo[e][1,2]oxathiine 2,2-dioxides were hydrogenated to give the target products in high yields (92–99%) with excellent enantioselectivities (up to 99.7% ee) using our catalytic system. This reaction provides
描述了一种高效的(S)-Ir / In-BiphPHOX催化的取代2 H-色烯和取代苯并[ e ] [1,2]草嘌呤2,2-二氧化物的不对称氢化反应。一系列2 H-色烯和苯并[ e ] [1,2]草嘌呤2,2-二氧化物被氢化,以高收率(92-99%)得到具有优异对映选择性(高达99.7%ee)的目标产物我们的催化系统。该反应为构建手性苯并六元含氧化合物提供了直接而有效的方法。
The first enantioselective synthesis of isoflavonoids: (R)- and (S)-isoflavans
作者:Marietjie Versteeg、Barend C. B. Bezuidenhoudt、Daneel Ferreira、Kenneth J. Swart
DOI:10.1039/c39950001317
日期:——
α-Benzylation of (+)- and (–)-N-phenylacetyl imidazolidinones with 2-O-methoxymethylbenzyl bromide, followed by reductive removal of the chiral auxiliary and cyclization, leads to isoflavans in excellent enantiomeric excess and yield.
An efficient RuPHOX−Ru catalyzed asymmetric cascade hydrogenation of 3-substitutedchromones has been achieved under mild reaction conditions, affording the corresponding chiral 3-substituted chromanols in high yields with excellent enantio- and diastereoselectivities. A dynamic kinetic resolution process occurs during the subsequent hydrogenation of the C=O double bond, which is responsible for the