Cyclopropanation Reactions of Pyroglutamic Acid-Derived Synthons with Akylidene Transfer Reagents

The cyclopropanation of unsaturated lactams 1 and 3 derived from pyroglutamic acid with nucleophilic alkylidene transfer reagents is investigated. Good-to-modest yields of cyclopropanes were obtained with most sulfur ylides explored. Syn/anti selectivity was found to be dependent on the synthon as well as the sulfur ylide. This cyclopropanation methodology is used in the synthesis of arginine and glutamic acid analogues.