Synthesis and reactions of a novel 3,4-didehydropyroglutamate derivative

Some reactions such as catalytic hydrogenation, Diels–Alder reaction, cyclopropanation, dihydroxylation, and Michael addition of a novel 3,4didehydropyroglutamate derivative, in which the carboxylic group is protected as an ABO ester, are examined and found to take place in a stereospecific manner giving 3- and/or 4-substituted pyroglutamate derivatives without loss of enantiomeric purity at the (alpha)-position.