Facile synthesis of unsaturated pyroglutaminol derivatives

A novel approach to the synthesis of unsaturated pyroglutaminol derivatives was developed. Condensation of a protected serine derivative with Meldrum’s acid followed by decarboxylative cyclization afforded a tetramic acid, which was then converted to a hydroxylactam using sodium borohydride. Iodine displacement of the hydroxyl group induced spontaneous elimination to afford unsaturated pyroglutaminol derivatives in good yields.