Robust and Efficient, Yet Uncatalyzed, Synthesis of Trialkylsilyl-Protected Cyanohydrins from Ketones
作者:Fabien L. Cabirol、Angela E. C. Lim、Ulf Hanefeld、Roger A. Sheldon、Ilya M. Lyapkalo
DOI:10.1021/jo702587e
日期:2008.3.1
High-yielding cyanosilylation of ketones with NaCN and various chlorotrialkylsilanes in DMSO proceeds smoothly without catalysis to give silyl-protected ketone cyanohydrins. The unique role of DMSO consists in rendering naked cyanide anions that reversibly add to the CO bond at the rate-determining step followed by fast trapping of the transient tertiary sodium cyanoalcoholates with chlorotrialkylsilanes
在DMSO中,用NaCN和各种氯三烷基硅烷对酮进行高产率的氰基甲硅烷基化反应可顺利进行,而无需催化,即可得到甲硅烷基保护的酮氰醇。DMSO的独特作用在于提供裸氰化物阴离子,该阴离子在速率确定步骤可逆地添加到C O键中,然后用氯代三烷基硅烷或原位生成的氰基三烷基硅烷快速捕获瞬态叔氰醇钠。制备上,该反应与应用昂贵的Me 3 SiCN的最著名的催化氰基硅烷化反应体系相匹配,并证明了在空间上被三烷基甲硅烷基保护的氰醇的合成中空前的效率。