Mechanistic studies on the rearrangement of 1-alkenyl-2-alkynylcyclopropanes: from allylic gold(I) cations to stable carbocations

Eva Tudela; Jairo González; Rubén Vicente; Javier Santamaría; Miguel A Rodríguez; Alfredo Ballesteros

doi:10.1002/anie.201407055

Mechanistic studies on the rearrangement of 1-alkenyl-2-alkynylcyclopropanes: from allylic gold(I) cations to stable carbocations

Angew Chem Int Ed Engl. 2014 Nov 3;53(45):12097-100. doi: 10.1002/anie.201407055. Epub 2014 Sep 15.

Authors

Eva Tudela¹, Jairo González, Rubén Vicente, Javier Santamaría, Miguel A Rodríguez, Alfredo Ballesteros

Affiliation

¹ Instituto de Química Organometálica "Enrique Moles" and Departamento de Química Orgánica e Inorgánica, Universidad de Oviedo, c/Julián Clavería 8, 33007, Oviedo (Spain).

PMID: 25223719
DOI: 10.1002/anie.201407055

Abstract

An allylic gold(I) cation, proposed as key intermediate in the gold-promoted rearrangement of 1,5-enynes bearing a fixed conformation, has been detected and characterized by NMR spectroscopy. Moreover, its participation in the overall transformation was confirmed. Computational studies indicate that the gold-catalyzed transformation occurs through an uncommon rearrangement. Additionally, this study led us to isolate and characterize a stable homoantiaromatic carbocation.

Keywords: allylic compounds; carbocations; gold; reactive intermediates; rearrangements.