Properties and Reactions of Substituted 1,2-Thiazetidine 1,1-Dioxides: Methylation of β-Sultams
作者:Martin Müller、Hans-Hartwig Otto
DOI:10.1002/ardp.19913240106
日期:——
Methylation of N‐substituted 1,2‐thiazetidine 1,1‐dioxides in the presence of lithium diisopropylamide (LDA) yields 4,4‐dimethyl derivatives. Monomethylation only occurs when one position at C‐4 is blocked by a silyl group, which, afterwards, can be removed by treatment with tetrabutylammonium fluoride (TBAF). A silyl protecting group at the nitrogen is easily removed by cleavage with TBAF on silica
在二异丙基氨基锂 (LDA) 存在下,N-取代的 1,2-噻唑烷 1,1-二氧化物的甲基化产生 4,4-二甲基衍生物。仅当 C-4 上的一个位置被甲硅烷基封闭时才会发生单甲基化,然后可以通过四丁基氟化铵 (TBAF) 处理去除甲硅烷基。在温和条件下,通过在硅胶上用 TBAF 裂解,可以轻松去除氮上的甲硅烷基保护基团。