Enantioselective dialkylation of 1,2-phthalicdicarboxaldehyde

A new two-step, one-pot procedure is reported for the enantioselective synthesis of C2-symmetric diols derived from 1,2-phthalicdicarboxaldehyde. The first step involves the enantioselective addition of a dialkylzinc compound to one of the aldehyde groups, affording a lactol organozinc derivative. In the second step this lactol derivative is converted to the appropriate diol with the aid of a Grignard reagent and subsequent hydrolysis. This methodology also allows the synthesis of unsymmetric diols.