Programmed Sequential Additions to Halogenated Mucononitriles

Abstract

Dihalomucononitriles were synthesized and their reactivity evaluated to assess their ability to function as linchpin reagents. Bis(2-chloroacrylonitrile) and bis(2-bromoacrylonitrile) were synthesized from 2,13-benzothiadiazole and shown to undergo conjugate addition reactions with both nitrogen (40–95% yield) and carbon nucleophiles (72–93% yield). Secondary amines were found to undergo monoadditions while carbon nucleophiles added twice. The sequence of addition of the nucleophiles could be controlled giving mixed addition products. The multicomponent coupling products could then be converted to natural product-like motifs using intramolecular cyclization reactions.