An unexpected facile domino reaction of alpha,beta-acetylenic gamma-hydroxy nitriles with arenecarboxylic acids (Et(3)N, MeCN, 20-25 degrees C, 48 h) affords 4-cyano-3(2H)-furanones in 67-86% yield. The reaction is triggered by the addition of an arenecarboxylic acid to a triple bond, followed by the domino reaction sequence: intramolecular transesterification-enol formation and Claisen condensation of the ketoacetonitrile tautomer with ester functional group.

A Facile Linking of the Pyrrole Ring with Functionalized 3(2H)-Furanone Moieties. -(MAL'KINA, A. G.; SHEMYAKINA, O. A.; STEPANOV, A. V.; VOLOSTNYKH, O. G.; USHAKOV, I. A.; SOBENINA, L. N.; BORODINA, T. N.; SMIRNOV, V. I.; TROFIMOV*, B. A.; Synthesis 48 (2016) 02, 271-280, http://dx.doi.org/10.1055/s-0035-1560754 ; A. E. Favorsky Inst. Chem., Sib. Branch, Russ. Acad. Sci., Irkutsk 664033, Russia; Eng.) -M. Tismer 23-044

Configurational assignment and conformational analysis of a series of iminodihydrofurans obtained from cyanoacetylenic alcohols were performed on the basis of experimental measurements and high-level ab initio calculations of their (13)C-(13)C spin-spin coupling constants. The title compounds were shown to form and exist in solution as the individual Z isomers, adopting the orthogonal orientation of the amino, alkylamino and dialkylamino groups and the s-trans orientation of the CONH(2) group at the C(4) position of the 2,5-dihydro-2-iminofuran moiety.

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The popular organic superbases 1,5‐diazabicyclo[4.3.0]non‐5‐ene (DBN) and 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) underwent annulation with electron‐deficient propargylic alcohols [EWG = CN, C(O)Ph, CO2Me] to afford functionalized condensed hexahydropyrimidine systems, [1,3]oxazolo[3,2‐a]pyrrolo[2,1‐b]hexahydropyrimidines and [1,3]oxazolo[3′,2′:3,4] hexahydropyrimido[1,2‐a]azepines, in good to high yields. The reactions proceeded regioselectively and, in most cases, stereoselectively under mild conditions (without catalyst, 20–25 °C). The synthesized compounds, owing to their potential rich chemistry, are novel promising precursors for pyrimidine‐based pharmaceuticals.

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