Short and efficient enantioselective synthesis of cis and trans pyrrolidine-2,5 dicarboxylic acids
作者:Jesús Ezquerra、Almudena Rubio、Concepción Pedregal、Gema Sanz、Jesús H. Rodriguez、José L. García Ruano
DOI:10.1016/s0040-4039(00)74065-2
日期:1993.7
N-BOC-ethyl pyroglutamate 1 undergoes nucleophilic ring opening with lithium methyl p-tolyl sulfinyl anion delivering the p-tolylketosulfoxide 2. Treatment of 2 with TFA gave rise to a mixture of thioesters 3a,3b. The hydrolysis of 3b afforded (2S, 5S) pirrolidine-2,5 dicarboxylic acid 5, a constituent of the red Alga . Under Pummerer reaction conditions (TFAA/Pyr), 2 yielded the 5-oxo-L-pipecolic