Synthesis of Enantioenriched Tertiary Boronic Esters by the Lithiation/Borylation of Secondary Alkyl Benzoates
作者:Alexander P. Pulis、Daniel J. Blair、Eva Torres、Varinder K. Aggarwal
DOI:10.1021/ja409100y
日期:2013.10.30
range of neopentyl boronic esters which, after 1,2-metalate rearrangement and oxidation, gave a range of tertiary alcohols in high yield and universally high er. Further functional group transformations of the tertiary boronic esters were demonstrated (conversion to quaternary centers, C-tertiary amines) together with application of the methodology to the synthesis of the simplest unbranched hydrocarbon
据报道,简单的仲 2,4,6-三异丙基苯甲酸酯 (TIB 酯) 和仲二烷基 N,N-二异丙基氨基甲酸酯可抵抗强碱的去质子化。我们发现 sBuLi(1.6 当量)和 TMEDA(6 当量)在 CPME 中在 -60 °C 下的组合能够使未活化的仲二烷基 TIB 酯去质子化,但不能使氨基甲酸酯去质子化。这些碳负离子与一系列新戊基硼酸酯反应,在 1,2-金属酸盐重排和氧化后,以高产率和普遍更高的效率得到一系列叔醇。证明了叔硼酸酯的进一步官能团转化(转化为季中心,C-叔胺)以及该方法应用于合成最简单的带有季中心的无支链烃,