1,4-Diazabicyclo[2.2.2]octane Trifluoroacetate: A Highly Efficient Organocatalyst for the Cyanosilylation of Carbonyl Compounds under Solvent Free Condition

Salts of DABCO (1,4-diazabicyclo[2.2.2]octane) were synthesised. The catalytic activities of these salts (0.125-1mol%) were evaluated for cyanosilylation of various aldehydes and ketones under solvent-free conditions using TMSCN (trimethylsilyl cyanide). Aldehydes were found to more reactive compared to the ketones and excellent yields of corresponding cyanosilylether were achieved within 5min to 54h. Cynaosilylation of aldehydes and ketones with electron withdrawing group found to be more reactive than the aldehydes and ketones bearing electron donating group. Silylcyanation of isatin and its derivatives was carried out and the corresponding products were obtained in 74-90% yields after 3-10 minutes. We also demonstrated that the catalyst could deprotect the TMS group of cyanosilylether in methanol in quantitative yield.