title: Rh-Catalyzed rearrangement of vinylcyclopropane to 1,3-diene units attached to N-heterocycles.
abstract: Dienes embedded in quinolizidine and indolizidine structures can be prepared in four steps from cyclic nitrones and bicyclopropylidene. The key intermediates α-spirocyclopropanated N-heterocyclic ketones, generated via a domino 1,3-dipolar cycloaddition/thermal rearrangement sequence, were converted by Wittig methylenation to the corresponding vinylcyclopropanes (VCPs), which underwent rearrangement to 1,3-dienes in the presence of the Wilkinson Rh(I) complex under microwave heating. The previously unexplored Rh(I)-catalyzed opening of the VCP moiety embedded in an azapolycyclic system occurs at high temperature (110-130 °C) to afford the corresponding 1,3-dienes in moderate yield (34-53%).
authors: Dipartimento di Chimica "Ugo Schiff", Università degli Studi di Firenze, Via della Lastruccia 13, 50019 Sesto Fiorentino (FI), Italy.
authors: Franca M
authors: FM
authors: Cordero
authors: Carolina
authors: C
authors: Vurchio
authors: Stefano
authors: S
authors: Cicchi
authors: Armin
authors: A
authors: de Meijere
authors: Alberto
authors: A
authors: Brandi