Titanium and zirconium benzofuranoxides. Crystal structures and catalytic properties

摘要

Reactions of Ti(OiPr)(4) or Zr(OEt)(4) with 4 equivalents of 2,3-dihydro-2,2-dimethyl-7-benzofuranol (ddbfoH) in toluene gave neutral complexes that in the solid state are dimers of [Ti(mu-ddbfo)(2)(ddbfo)(6)] and [Zr(ddbfo)(3)(EtOH)(mu-EtO)](2) composition. The former could also be conveniently synthesized in a direct reaction of TiCl4 with ddbfoH. This air-stable aryloxo compound was found to initiate living ring-opening polymerization of lactides affording polyesters with narrow molecular weight distribution. It also catalyzed addition of terminal acetylenes to aryl aldehydes.