NOVEL [3-SUBSTITUTED ARYL RADICALS WITH ALKYNES(2] RADICAL ANNULATIONS OF CYANO)

New radical annulation reactions are described involving addition of o rtho-cyano-substituted aryl radicals to alkynes. Addition of the aryl radical to the C-C triple bond gives rise to a vinyl radical, whose cy clisation onto the carbon atom of the nitrile moiety produces an iminy l radical. The final reaction products derive from the iminyl by hydro gen abstraction - followed by hydrolysis -, dimerisation, or cyclisati on onto another aromatic ring. In the last case, new nitrogen heterocy cles are formed through a novel application of the radical addition, t andem cyclisation strategy. (C) 1998 Elsevier Science Ltd. All rights reserved.