STEREOSELECTIVE REACTIONS OF LITHIUM ENOLATES DERIVED FROM N-BOC PROTECTED PYROGLUTAMIC ESTERS
STEREOSELECTIVE REACTIONS OF LITHIUM ENOLATES DERIVED FROM N-BOC PROTECTED PYROGLUTAMIC ESTERS
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DOI：
10.1016/s0040-4020(01)96272-6
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发表时间：
1993-09-17
期刊：
影响因子：
2.1
通讯作者：
SANCHEZFERRANDO, F
中科院分区：
文献类型：
--
作者：
EZQUERRA, J;PEDREGAL, C;SANCHEZFERRANDO, F
N-Boc保护的焦谷氨酸乙酯或叔丁酯的烯醇化锂与亲电试剂以良好的产率反应，而没有手性中心的差向异构化。对于苄基溴，该过程是立体特异性的，仅产生反式异构体。然而，与其他反应性亲电体的2：1的反式/顺式非对映异构体的混合物，得到的酯基团的空间体积无关。
The lithium enolates of N-Boc protected pyroglutamic ethyl or tert-butyl esters react with electrophiles in good yield without epimerization of the chiral centre. With benzyl bromides the process is stereospecific, yielding exclusively the trans isomer. However, with other reactive electrophiles a 2:1 trans/cis diastereomeric mixture was obtained, regardless of the steric bulk of the ester group.