Pyridine chromium tricarbonyl complexes: completely stereoselective α,α-dialkylation of 2-methylpyridine tricarbonylchromium
作者:Stephen G. Davies、Mark R. Shipton
DOI:10.1039/c39900001780
日期:——
Sequential α-deprotonationâmethylation of (RS)-2-(1-but-3-enyl)pyridine tricarbonylchromium generates completely stereoselectively (N-RS, α-RS)-[2-(2-pent-4-enyl)pyridine]tricarbonylchromium which in turn undergoes completely stereoselective nucleophilic methylation (MeLi) to generate after methyl iodide quench (N-RS,2-SR,α-RS)-[exo-N,2-dimethyl-6-(2-pent-4-enyl)-1,2-dihydropyridine]tricarbonylchromium.
(RS)-2-(1-丁-3-烯基)吡啶三羰基铬的顺序δ-去质子化甲基化生成完全立体选择性的(N-RS、(N-RS,2-SR,δ-RS)-[外-N,2-二甲基-6-(2-戊-4-烯基)-1,2-二氢吡啶]三羰基铬,再经过完全立体选择性的亲核甲基化反应(MeLi),在碘甲烷淬灭后生成(N-RS,2-SR,δ-RS)-[外-N,2-二甲基-6-(2-戊-4-烯基)-1,2-二氢吡啶]三羰基铬。