The intramolecular Pd(II)-mediated cyclization of 1-allyl-2-indolecarboxamides leads to pyrazino[1,2-a]indoles through the conversion of the olefinic C-H bond into a C-N bond by reaction with an amide group. When operating on the allylamide, a domino process was observed with a double C-H functionalization.
Ring-closing metathesis of 3-allyl- or 3-vinylindole-2-carboxylic derivatives gave access to fused seven- to eight-membered lactams; 1-allylindole-2-carboxylic homoallylamide afforded the nine-membered lactam. The reactivity of 1,3-disubstituted-2-carboxylic acidderivatives was also investigated.