The first asymmetric catalytic halo aldol reaction of β-iodo allenoates with aldehydes by using chiral salen catalyst

The first asymmetric catalytic halo aldol reaction of β-iodo allenoates with aldehydes was established. The reaction was successfully achieved by using (R,R)-SalenAlCl as the chiral catalyst and LiI as an additive at 0°C in dichloromethane. Moderate to good yields and up to 62% ee were obtained. The new system showed a good substrate scope in which both aromatic aldehydes and aliphatic aldehydes can be employed. The reaction provided the first catalytic and enantioselective approach to chiral β-iodo Baylis-Hillman ester adducts.