Design and development of intramolecular doubly vinylogous Michael addition to access 3-aryl substituted 2-alkenyl-benzofurans and -indoles.

Herein, we have disclosed a rare example of an intramolecular doubly vinylogous Michael addition (DVMA). The reaction design exploits the innate reactivity of -heteroatom substituted -quinone methide (-QM) derivatives. The sequential reaction of -QMs and activated allyl halides proceeds through heteroatom-allylation, DVMA and oxidation to furnish a diverse range of 2-alkenyl benzofuran and 2-alkenyl indole derivatives in high yields.