Chiral Carbanions, Part 4:Borylation of (Trimethylsilyl)methyl<i>N</i>,<i>N</i>-Dialkylcarbamates - Diastereoselectivity and Structural Studies
作者:Friedrich Hammerschmidt、Biljana Peric Simov、Agnieszka Rohn、Lothar Brecker、Gerald Giester
DOI:10.1055/s-2004-831237
日期:——
(Trimethylsilyl)methyl carbamates were prepared from (trimethylsilyl)methanol and N,N-dialkylcarbamoyl chlorides and were metalated by s-BuLi/TMEDA. The configurationally labile lithiated carbamates were reacted with borates derived from (+)-pinane-2,3-diol to give boronates diastereoselectively (yields up to 84%, dr up to 17:1). The absolute configurations at the boron-bearing carbon atoms of three
(三甲基甲硅烷基)甲基氨基甲酸酯由(三甲基甲硅烷基)甲醇和 N,N-二烷基氨基甲酰氯制备,并通过 s-BuLi/TMEDA 进行金属化。构型不稳定的锂化氨基甲酸酯与衍生自 (+)-pineane-2,3-diol 的硼酸盐反应生成非对映选择性硼酸盐(产率高达 84%,dr 高达 17:1)。三种硼酸盐的含硼碳原子的绝对构型由单晶 X 射线结构分析确定。