Rhodium(II)-catalyzed intramolecular annulation of 1-sulfonyl-1,2,3-triazoles with pyrrole and indole rings: facile synthesis of N-bridgehead azepine skeletons.

A convenient and efficient synthetic method has been developed to construct highly functionalized N-bridgehead azepine skeletons, which are of great importance in biological and pharmaceutical industry. The reaction proceeds through a rhodium(II) azavinyl carbene intermediate, which initiated the intramolecular C-H functionalization with pyrrolyl and indolyl rings. A variety of azepine derivatives were obtained in moderate to good yields under mild reaction conditions with high chemoselectivity.