Formal synthesis of (+)-lactacystin based on a novel radical cyclisation of an α-ethynyl substituted serine
作者:Christopher J Brennan、Gerald Pattenden、Gwenaëlla Rescourio
DOI:10.1016/j.tetlet.2003.10.022
日期:2003.12
5-exo-dig radical cyclisation of the bromoamide 7 produced from the enantiopure α-ethynyl substituted amino alcohol 5 led to the pyrrolidinone 8 (2:1 α:β epimers) in 70% yield. Oxidative cleavage of the alkene bond in 8, followed by a stereoselective α-methylsulfanylation of the resulting 4-keto derivative 9, next led to the methylsulfanyl derivative 10. Finally, the pyrrolidinone derivative 10 was
由对映体纯的α-乙炔基取代的氨基醇5产生的溴酰胺7的非对映选择性的5- exo- dig自由基环化产生吡咯烷酮8(2:1α:β差向异构体),产率为70%。8中烯烃键的氧化裂解,随后是生成的4-酮衍生物9的立体选择性α-甲基磺酰化,然后生成甲基硫烷基衍生物10。最后,将吡咯烷酮衍生物10转化为先前用于(+)-lactacystin的对映选择性合成的关键中间体12。