Robust and Efficient, Yet Uncatalyzed, Synthesis of Trialkylsilyl-Protected Cyanohydrins from Ketones
Fabien L. Cabirol, Angela E. C. Lim, Ulf Hanefeld, Roger A. Sheldon and Ilya M. Lyapkalo*
*Institute of Organic Chemistry and Biochemistry, Flemingovo n. 2., 166 10 Prague 6, Czech Republic, Email: ilya.lyapkalouochb.cas.cz
F. L. Cabirol, A. E. C. Lim, U. Hanefeld, R. A. Sheldon, I. M. Lyapkalo, J. Org. Chem., 2008, 73, 2446-2449.
Uncatalyzed cyanosilylation of ketones with NaCN and various chlorotrialkylsilanes in DMSO proceeds smoothly to give silyl-protected cyanohydrins in excellent yields. The role of DMSO consists in rendering naked cyanide anions that reversibly add to the carbonyl at the rate-determining step followed by fast sillylation of the transient tertiary alcoholates with chlorotrialkylsilanes or in situ generated cyanotrialkylsilanes.
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