Diastereoselective addition of metalated isoindolin-1-ones to aldehydes. Stereoselective preparation of (E)-3-arylideneisoindolin-1-ones

Lithiated isoindolinones react with aromatic aldehydes to afford 3-hydroxybenzyl derivatives with high diastereoselectivity. Dehydration of erythro and threo adducts through an E1cb mechanism gives rise indiscriminately to the (E)-arylideneisoindolinones.