摘要:
[GRAPHICS]Acyclic Psi[(E)-CH=CMe]- and Psi[(2)-CH Me]-type dipeptide isosteres were efficiently synthesized. In a key reaction, alpha-alkylation of gamma-mesyloxy,beta-methyl-alpha,beta-unsaturated esters with organocyanocuprates in diethyl ether or tetrahydrofuran preferentially afforded the V[(E)-CH=CMe]- or Psi[(2)-CH=CMe]-isomer, respectively, via anti-S(N)2' mechanism.