Bismuth (III)-Catalyzed Regioselective Alkylation of Tetrahydro-quinolines and indolines towards the synthesis of Bioactive core-Biaryl oxindole and CYP19 inhibitor

Bismuth (III)-catalyzed regioselective functionalization at the C-6 position of tetrahydroquinolines and C-5 position of indolines have been demonstrated. For the first time, one-pot symmetrical and unsymmetrical arylation of isatins with tetrahydroquinolines was accomplished giving a completely new biaryl oxindole product skeleton in good to excellent yields. Most importantly, this protocol leads to the formation of a highly strained quaternary carbon stereogenic center which is a challenging task. Benzhydryl and 1-phenylethyl trichloroacetimidates have been used as the alkylating partners to functionalize the C-6 and C-5 positions of tetrahydroquinolines and indolines respectively. The scope of the developed methodology has been extended for the synthesis of bioactive CYP19-inhibitor analogs.