The chemistry of organoborates. 9. A regiospecific and highly stereoselective construction of trisubstituted αβ-unsaturated ketones, tetrasubstituted αβ-unsaturated ketones and specifically protected 1,3-diketones from alkynyltrialkylborates
作者:Andrew Pelter、M. Eamon Colclough
DOI:10.1016/0040-4020(94)00953-r
日期:1995.1
fashion such that the dioxolanium group and the migrating group are on the same side of the new alkene intermediate. Hydrolysis of the intermediate yields Z-trisubstituted αβ-unsaturated ketones in which all three substituents have different origins and can be independently varied. Oxidation of the intermediates gives β-ketoacetals, which are regiospecifically protected 1,3-diketones. If the initial intermediates
炔基三烷基硼酸锂与氟磺酸二恶唑鎓盐以高度立体选择性的方式反应,使得二恶戊鎓基团和迁移基团在新的烯烃中间体的同一侧。中间体的水解产生Z-三取代的αβ-不饱和酮,其中所有三个取代基具有不同的起源并且可以独立地变化。中间体的氧化产生β-酮缩醛,它是区域特异性保护的1,3-二酮。如果允许初始中间体静置,则将发生另一种迁移,并导致四取代的αβ-不饱和酮。