Facile Synthesis of Cyanide and Isocyanides from CO.

The reaction of K[N(SiMe3 )2 ] with 13 CO proceeds in C6 D6 or THF affording K13 CN and O(SiMe3 )2 under mild conditions as confirmed by crystallographic characterization of K(18-crown-6)CN. Similarly reaction of the alkali metal amides, M[N(SiR3 )R'] (M=Li, K; R=Ph, Me; R'=alkyl, aryl) provides the corresponding 13 C labeled isocyanide RN13 C and MOSiR3 , generally in high yields. In some instances, the use of the sterically bulky Ph3 Si-substituent is required to preclude 1,2-silyl migration affording the silylcarbamoyl salt M[Me3 SiC(O)NR']. These reactions have been used to obtain 19 examples of 13 C labelled isocyanides, and several examples of gram scale reactions are reported. The mechanism of the reactions is probed via reliable DFT calculations.