Tandem [4C + 2C] cyclization reaction of α-acetyl-α-oxo ketene dithioacetals and acrylonitrile: A straightforward synthesis of polysubstituted cyclohex-3-enones

In the investigation, the tandem (Michael addition/nucleophilic cyclization/Michael addition reactions) [4C + 2C] cyclization reaction of α-acetyl-α-oxo ketene dithioacetals as four-carbon synthons and acrylonitrile as two-carbon components is developed under mild reaction conditions. In the presence of 1 equivalents of t-BuOK, the tandem [4C + 2C] cyclization reaction of α-acetyl-α-oxo ketene dithioacetals and acrylonitrile efficiently occur to polysubstituted cyclohex-3-enones in 60–72% yields. Twenty-four new products were synthesized and characterized by NMR, FTIR, HRMS and X-ray crystallography. The approach exhibits fascinating features such less expensive, efficient and operationally convenient, ease of scale-up.