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A Microwave-Mediated Catalyst-and Solvent-Free Regioselective Biginelli Reaction in the Synthesis of Highly Functionalized Novel Tetrahydropyrimidines. -The process is completely regioselective and affords good to excellent yields of the desired pyrimidine system within a short time. -(HARIKRISHNAN, P. S.; RAJESH, S. M.; PERUMAL*, S.; ALMANSOUR, A. I.; Tetrahedron Lett. 54 (2013) 9, 1076-1079, http://dx.

A library of novel trans-ethyl 5-aroyl-4-aryl-2-[(arylsulfonyl)methyl]-4,5-dihydrofuran-3-carboxylates were synthesized regio-and stereoselectively in good yields by a three-component domino reaction of ethyl-3-oxo-4-(arylsulfonyl)butanoates, aromatic aldehydes and Nphenacylpyridinium bromide in presence of triethylamine in acetonitrile under heating. This transformation generates C-O, C-C and C=C bonds and presumably proceeds via an α,β-unsaturated ketosulfonyl ester generation/Michael addition/intramolecular cyclisation domino sequence.

Depending on the educt ratio and the amount of NH4OAc used, the condensation of 3‐oxo‐4‐arylsulfonylbutanoates (I) with aromatic aldehydes yields densely functionalized cyclohexadienes (III) or pyridines (V).