Enantioselective 1,4-addition of arylboronic acids to α,β-unsaturated carbonyl compounds catalyzed by rhodium(I)-chiral phosphoramidite complexes
作者:Kazunori Kurihara、Noriyuki Sugishita、Kengo Oshita、Dongguo Piao、Yasunori Yamamoto、Norio Miyaura
DOI:10.1016/j.jorganchem.2006.04.042
日期:2007.1
and P(NMe2)3 as a new ligand for rhodium(I)-catalyzed asymmetric 1,4-addition of arylboronic acids to α,β-unsaturated carbonyl compounds. The effects of 5a and Feringa’s monodentate phosphoramidite (4, R1, R2 = Et) on the yields and enantioselectivities were fully investigated. The reaction was significantly accelerated in the presence of a base such as KOH and Et3N, allowing the reaction to be completed
由Shibasaki's联结的-(R)-BINOL和P(NMe 2)3合成手性双齿亚磷酰胺(5a),作为铑(I)催化的芳基硼酸不对称1,4-加成到α,β-的新配体不饱和羰基化合物。充分研究了5a和Feringa单齿亚磷酰胺(4,R 1,R 2 = Et)对产率和对映选择性的影响。在碱例如KOH和Et 3的存在下,反应显着加速N,可在低于50°C的温度下完成反应。在加入到环状烯酮,如2-环戊烯酮,2-环己烯酮,在50℃下在存在2-cycloheptenone的[Rh(COE)2 CL] 2 - 4(R 1,R 2 = ET)复合导致对映选择性高达98%,尽管对无环烯酮(0-70%ee)效果不佳。另一方面,[Rh(nbd)2 ] BF 4和5a之间的络合物在室温下在存在Et 3的情况下于2小时内完成了向环烯酮的加成反应。N的产率为86–99%,ee为96–99.8%。该催化剂对无环烯酮也有