Organocatalytic Regiodivergent Ring Expansion of Cyclobutanones for the Enantioselective Synthesis of Azepino[1,2-<i>a</i>]indoles and Cyclohepta[<i>b</i>]indoles
作者:Wu-Lin Yang、Wen Li、Zhong-Tao Yang、Wei-Ping Deng
DOI:10.1021/acs.orglett.0c01406
日期:2020.5.15
series of azepino[1,2-a]indoles were obtained with exclusive regioselectivities and high diastereo- and enantioselectivities (up to >20:1 dr, 96% ee) with the application of the N1 nucleophilic site of the indole nucleus. Meanwhile, various cyclohepta[b]indoles could be accessed with high enantiopurity (up to 96% ee) through the Michael addition/boron-trifluoride-etherate-promoted indole C3-attack
提出了具有2-硝基乙烯基吲哚的吸电子基团活化的环丁酮的区域发散性有机催化对映选择性迈克尔加成/三原子环膨胀序列。通过使用吲哚核的N1亲核位点,获得了一系列具有独特区域选择性以及高非对映和对映选择性(最高> 20:1 dr,96%ee)的azepino [1,2-a]吲哚。同时,通过迈克尔加成反应/三氟化硼-醚化物促进的吲哚C3-攻击环的扩展过程,可以得到高对映体纯度(最高ee为96%)的各种环庚[b]吲哚。