Unexpected proximal ring opening reactions of benzocyclobutene complexes

Abstract
An unexpected opening of a proximal bond in the anellated four-membered ring of benzocyclobutene tricarbonylchromium(0) complexes occurs when the 1-hydroxy-1-hex-5-enyl complex 2 is treated with base: in general, rupture of the distal bond is observed. The reaction of tricarbonyl-η6-(1-oxobenzocyclobutene)chromium(0)1 with primary amines also causes a proximal ring-opening reaction.