Efficient access to novel hexahydro-chromene and tetrahydro-pyrano[2,3-d]pyrimidine-annulated benzo-δ-sultones via a domino Knoevenagel-hetero-Diels-Alder reaction in water

An efficient catalyst-free, diastereosective synthesis of novel hexahydro-chromene and tetrahydro-pyrano[2,3-d]pyrimidine-annulated benzo-delta-sultones is described. A number of 2-formyl-4-phenyl (E)-2-phenylethenesulfonates were synthesized and underwent a one-pot domino Knoevenagel-hetero-Diels-s-Alder reaction, respectively, with dimedone and N,N-dimethylbarbituric acid in water, affording the desired products in moderate to excellent yields. (C) 2011 Elsevier Ltd. All rights reserved.