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
The synthetic utility of N-heterocyclic carbenes was demonstrated by the trialkylsilylcyanation of aldehydes, ketones and imines. In the presence of a catalytic amount of 3a, the reactions with Me3SiCN proceeded smoothly to give the corresponding cyanohydrin trimethylsilyl ethers or amino nitrile derivatives in good to excellent yields.