B(C6F5)3-catalyzed β-C(sp3)–H alkylation of tertiary amines with 2-aryl-3H-indol-3-ones

Abstract

The β-C–H functionalization of amines is one of the most powerful tools for the synthesis of saturated nitrogen-containing heterocycles in organic synthesis. However, the β-C–H functionalization of amines via redox-neutral addition with cyclic-ketimines is still unprecedented. Herein, the β-C–H functionalization of tertiary amines is described, providing the corresponding 1,3-diamines containing the indolin-3-one moiety in high yields via the B(C₆F₅)₃-catalyzed borrowing hydrogen strategy. According to the experimental results, a possible catalytic cycle has been proposed to rationalize the process of this reaction. Notably, the β-C–H alkylation of amines is external oxidant- and transition-metal-free, which makes a significant contribution to promoting economical chemical synthesis.