Domino Conversions of Allyl Tetronates and 4‐Allyloxycoumarins to all‐trans 1,3,4,5‐Tetrasubstituted γ‐Butyrolactams.

Abstract

Pyrrole derivatives R 0120Domino Conversions of Allyl Tetronates and 4-Allyloxycoumarins to all-trans 1,3,4,5-Tetrasubstituted γ-Butyrolactams. -A regio-and stereoselective one-pot synthesis of the title compounds proceeds via spirocyclopropanes of type (XVI), which undergo ring-opening in the presence of amines with R > -Et. In the case of (IIIc) andV), 10% of 3,4-cis-isomers are additionally obtained; however, their structures are not further specified. Reaction of diastereopure (XVI) with the soft nucleophile cyclohexene under ZnCl2 catalysis furnishes (XVIII) as the sole product of a formal [5+1] cycloaddition. -(SCHOBERT*, R.; BIESER, A.; MULLEN, G.; GORDON, G.; Tetrahedron Lett. 46 (2005) 33, 5459-5462; Lab. Org. Chem., Univ. Bayreuth, D-95440 Bayreuth, Germany; Eng.) -R. Steudel 48-131