Beschreibung:
<jats:title>Abstract</jats:title><jats:p>Synthesis of the title compounds is described, starting from alkylation of the pyroglutaminol‐acetal <jats:bold>4a</jats:bold><jats:sup>[1]</jats:sup> at the α‐lactam position C‐6 with methyl iodide. Subsequent addition of 2‐cyclohexen‐1‐one led to diastereoselective formation of the 1,2‐aldol addition product <jats:bold>7b/7c</jats:bold>, which after dehydratization was aromatized with DDQ to yield the 6‐methyl‐6‐phenyl derivative <jats:bold>7h.</jats:bold> Acetal cleavage and Jones oxidation yielded 4,4‐disubstituted, enantiomerically pure pyroglutamic acid <jats:bold>3b.</jats:bold> X‐ray analysis confirmed the assignment of the configuration of the newly created chiral centre.</jats:p>