Substrate-controlled chemoselective assembly of coumarins and Morita-Baylis-Hillman alcohols from salicylaldehydes with acrylates

Substrate-controlled divergent reactions of between salicylaldehydes and acrylates have been developed. By using methyl acrylate as the substrate with salicylaldehydes, a domino reaction was established, delivering coumarins with good yield (up to 81% yields) and high chemoselectivity under mild conditions. Whereas the methyl acrylate was changed to tert-butyl acrylate or iso-propyl acrylate, the classical Morita - Baylis - Hillman adducts were produced in good yields (up to 75% yields) under near exclusivity under the otherwise identical reaction conditions, without any other competitive products. Additionally, the synthetic utility of the present methodology was further demonstrated by synthetic transformation. The structure of the typical product was unambiguously established by single crystal X-ray diffraction analysis.