A novel approach to Morita–Baylis–Hillman (MBH) lactones via the Lewis acid-promoted couplings of α,β-unsaturated lactone with aldehydes

The Morita–Baylis–Hillman (MBH)-type reaction of α,β unsaturated δ-lactone with various aldehydes has been achieved without the direct use of a Lewis base. The new MBH process can be conveniently carried out by the slow addition of the diethylaluminum iodide into the solution of lactone and aldehyde in dichloromethane at 0°C. Modest to good yields were obtained (50–65%) for eight examples.