4a: R= R'= CH3; R*'= t-Bu b: R= i-Pr; R'= H; R”= PhCH2 c: R= H; R'= i-Pr; R= PhCH2 important to synthesize these new methano amino acids, not only for their probable ability to stabilize'adjacent peptide linkages, but also to examine the possibility that peptides containing them might be enzyme inhibitom2 The simplest and most direct approach to the synthesis of 2, 3-methano amino acids, although not operationally the safest, is the “diazo ...