To determine what conformations of L-glutamate (LG~ u) activate that compound's different receptors in the mammalian central nervous system, four diastereomeric L-2- (carboxycyclopropyl) glycines, 1-4, which are conformationally conetrainsd aualogues of the extended and folded conformers of LGlu, were synthesized and subjected to neutrophysiological amy. Compounds 1-4 were efficiently synthesized from chiral amino ...