Cycloisomerization of aromatic homo- and bis-homopropargylic alcohols via catalytic Ru vinylidenes: formation of benzofurans and isochromenes

Org Lett. 2009 Nov 19;11(22):5350-3. doi: 10.1021/ol902212h.

Abstract

Ru-catalyzed cycloisomerizations of aromatic homo- and bis-homopropargylic alcohols effectively afford benzofurans and isochromenes. These processes proved to be chemo- and regioselective (5-, and 6-endo cyclizations) derived from key Ru vinylidene intermediates. The presence of an amine/ammonium base-acid pair is crucial for the catalytic cycle.