Efficient regioselective synthesis of indole N-carboximidamides and N-carboximidoates by a sequential Aza-Wittig/Ag(I)-catalyzed cyclization.

An efficient Ag(I)-catalyzed regioselective cyclization of (2-alkynylphenyl)guanidine or (2-alkynylphenyl)isourea to indole N-carboximidamides or N-carboximidoates has been developed. The approach has the advantages of high regioselectivity, mild reaction conditions, easily accessible starting materials, and good yields.