Tetrahedron

Synthesis of pyrrolizines by intramolecular capture of 1, 4-dipolar intermediates in reactions of enamines with dimethyl acetylenedicarboxylate

…, WP Trompenaars, DN Reinhoudt, S Harkema…

Index: Verboom, W.; Visser, G. W.; Trompenaars, W. P.; Reinhoudt, D. N.; Harkema, S.; Hummel, G. J. van Tetrahedron, 1981 , vol. 37, # 20 p. 3525 - 3533

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Citation Number: 30

Abstract

Solvent polarity and reaction temperature strongly influence the reactions of dimethyl acetylenedicar-boxylate (DMAD) with 1-pyrrolidinyl enamines of acyclic and cyclic ketones. Whereas DMAD and 1-[1-phenyl-2-(phenylthio) ethenyl] pyrrolidine (3) give only a mixture of the isomeric 1, 3-butadienes (5) in apolar solvents, in methanol the main product is the pyrrolizine 7, together with 5. Again in methanol, DMAD reacts at 0-5° with 8, 9 and 10 to ...