An efficient conjugate hydrocyanation of chalcones and related enones with TMSCN under solvent- and additive-free microwave conditions

A first example of solvent- and additive-free 1,4-addition reaction of α,β-unsaturated ketones such as chalcones, 3-nonen-2-one and benzalacetone with trimethylsilyl cyanide (TMSCN) is described. The addition of TMSCN to chalcones, 3-nonen-2-one, and benzalacetone under microwave irradiation in the absence of Lewis or Brønsted acids and solvents, yielded the corresponding β-cyanoketones in good to moderate yields, as quite rapidly as in 5 min. No systematic substituent effect of chalcones on the yields was observed. No reaction of α,β-unsaturated esters such as methyl cinnamate with TMSCN took place under the same conditions.