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
N-BOC-乙基焦谷
氨酸1所经历亲核开环,与
锂甲基对
甲苯亚磺酰基的阴离子递送的p tolylketosulfoxide 2。用TFA处理2得到
硫酯3a,3b的混合物。3b的
水解得到(2S,5S)
吡咯烷-2,5-二
羧酸5,其为红色藻类的成分。在Pummerer反应条件下(
TFAA / Pyr),2产生5-氧代-L-
哌酸衍
生物6。