Copper-catalyzed C-3 benzylation of quinoxalin-2(1 H )-ones with benzylsulfonyl hydrazides.

An unprecedented use of benzylsulfonyl hydrazides as benzylating agents has been demonstrated in the direct C-3 benzylation of quinoxalin-2(1 H )-ones. A range of benzylsulfonyl hydrazides participated in the C-3 benzylation of quinoxalin-2(1 H )-ones with CuCN as the catalyst and DTBP as the oxidant, delivering structurally diverse 3-benzylquinoxalin-2(1 H )-ones in moderate to good yields.