Acid-catalyzed efficient Friedel-Crafts reaction of indoles with N-Boc aminals

An effective Friedel-Crafts reaction between N-Boc aminals and N-Boc indoles catalyzed by copper(II) trifluoromethanesulfonate has been developed. The less accessible N-Boc imines could be generated in situ from N-Boc aminals. The reaction was achieved in moderate to good yields under mild conditions.