One-Pot Catalytic Asymmetric Synthesis of Tetrahydrocarbazoles

A one-pot
asymmetric synthesis of 1,2,3,4-tetrahydrocarbazoles
has been developed via an enantioselective [3 + 3] annulation of 2-alkynylindoles
and donor–acceptor cyclopropanes. In the presence of chiral
Lewis acids as catalysts, a series of optically active tetrahydrocarbazoles
were furnished in high yields (63–87%) with good to excellent
levels of enantioselectivity (up to 94% ee).

本研究开发了一种通过2-炔基吲哚与给体-受体环丙烷的对映选择性[3+3]环合反应，制备1,2,3,4-四氢咔唑的一锅法不对称合成策略。在以手性路易斯酸作为催化剂的反应体系中，可得到一系列光学活性的四氢咔唑产物，产率介于63%至87%之间，且具有良好至优异的对映选择性，最高对映体过量值（enantiomeric excess, ee）可达94%。