Trimethylsilylcyanation of heterocyclic imines catalysed by Lewis acids

The addition of Me3SiCN to Shiff bases 1a-8a, synthesized by the reaction o f furan and thiophene aldehydes with 3- and 4-aminobenzotrifluorides, has b een studied in the presence of various Lewis acids. A series of the corresp onding trifluoromethyl derivatives of heterocyclic alpha -aminonitriles 1-8 was synthesized in 38-80% isolated yields, It was found that 4A molecular sieves (MS) accelerate the addition and increase the yields of the products , The investigated catalysts are ranked by their activity in the following order: AlBr3 + 4AMS > AlBr3 > AlCl3 > Ti[O(iPr)](4). A single crystal of N- (5-methyl-2-thienylcyanomethyl)-3-trifluoromethyl-aniline was obtained and studied by X-ray diffraction, The results showed that it was the crystal of the (R) isomer of this compound. Copyright: (C) 2000 John Wiley & Sons, Lt d.