A New and Highly Effective Aldol Synthesis

Abstract
A new approach has been demonstrated for the regiospecific aldol synthesis by the simultaneous addition of α-halo carbonyl derivatives and aldehydes or ketones to a suspension of diethylaluminum chloride and zinc in tetrahydrofuran at low temperature. This technique is also employable under mild conditions for the Reformatsky reaction to give β-hiydroxy esters in excellent yield. One of the unique synthetic applications of this process is illustrated by the intramolecular cyclization of α-bromo esters of ω-hydroxy aldehyde, which produces macrolides, an important class of compounds in the antibiotic field.