Activation of alkynes by an α-diimine-stabilized Al–Al-bonded compound: insertion into the Al–Al bond or cycloaddition to AlN2C2 rings

Abstract

The reaction of dialumane, [L²⁻(THF)Al^II–Al^II(THF)L²⁻] (1, L = [(2,6-iPr₂C₆H₃)NC(Me)]₂), with the less reactive diphenylacetylene affords a new insertion product [L²⁻(THF)Al^III(PhCCPh)²⁻Al^III(THF)L²⁻] (2). Reaction of 1 with phenylacetylene (or 4-ethynyltoluene), however, proceeds through cycloaddition of alkynes to the AlN₂C₂ rings to produce bis(bicyclic) products (3a and 3b).