Under mild conditions the acyl group of acylzirconocene chloride 1 formed from an alkene or alkyne and [(C5 H5 )2 ZrHCl] reacts as an "unmasked" acyl anion. The Lewis acid mediated reactions with aldehydes that yield α-ketol products in high yields demonstrate the versatility of this reagent for C-C coupling.
SOUPPE, J.;NAMY, J-L.;KAGAN, H. B., TETRAHEDRON LETT., 1984, 25, N 27, 2869-2872