ZrCl₄-catalyzed X-C/C-C bond formation for the geometric selective synthesis of (E)-β-iodo aza Morita-Baylis-Hillman (MBH) adducts

A geometric selective synthesis of (E)-β-iodo and β-alkyl vinyl ketones (MBH amino adducts) has been developed through a three-component Mannich-type reaction. The reaction was conveniently conducted by generating 3-iodo allenolate intermediates via the α,β-unsaturated addition of TMS-I to 3-butyn-2-one followed by a carbonyl addition onto N-aryl imines in the presence of ZrCl₄ catalyst. The resulting β-iodo allylic amines can be readily converted into β-alkyl Morita-Baylis-Hillman adducts by performing Suzuki and Kumada cross-couplings.