Tetramethylguanidine (TMG)-catalyzed reductive spirocyclization of tryptamine derivatives with formic acid as a C1 synthon

Abstract

A reductive spirocyclization of tryptamine derivatives with formic acid as a C1 building block has been achieved via dearomatization. The reaction was catalyzed by a commercially available and cost-effective organic base, tetramethylguanidine (TMG). A variety of spiroindolenines were obtained in high yields under mild conditions.