1-Trifluoromethylisoquinolines from α-Benzylated Tosylmethyl Isocyanide Derivatives in a Modular Approach

The preparation of various 1-triftuoromethyli-soquinolines from alpha-benzylated tosylmethyl isotyanide derivatives and the commercial Togni reagent using a radical cascade is reported. The starting isocyanides are readily prepared in a modular sequence from commercial tosylmethyl isocyanide via sequential double a-alkylation, and the radical reaction proceeds under mild conditions, with high efficiency without any transition-metal catalyst via electron catalysis. This valuable protocol has been successfully applied to the total synthesis of CF3-mansouramycin B.