Application of HSAB Theory in the Selective Reduction of Quinoline

Abstract

Comprehensive SummaryIt is very important to develop efficient synthetic strategies for site‐specific functionalization of tetrahydroquinolines due to their indispensable roles in pharmaceutical and agrochemical industries. We apply hard/soft acid/base (HSAB) theory to selective reduction of quinoline and achieve a series of C3‐functionalized tetrahydroquinoline in high to excellent yields (up to 99%) under mild conditions with the catalysis of B(C6F5)3. A series of in situ NMR reactions are also performed to investigate this cascade reaction. Moreover, AB type monomer 6‐(dimethylsilyl) quinoline and AA/BB type monomer 6,6'‐biquinoline are synthesized for polymer synthesis, which represents the first example of silicon bridged polytetrahydroquinoline.