Synthesis 2015; 47(21): 3412-3422
DOI: 10.1055/s-0034-1378820
paper
© Georg Thieme Verlag Stuttgart · New York

Cobalt-Mediated Reactions of Oxazoles and Thiazoles with Alkynes

Michael J. Eichberg
Department of Chemistry, University of California at Berkeley, Berkeley, California 94720-1460, USA   Email: kpcv@berkeley.edu
,
Dominique Leca
Department of Chemistry, University of California at Berkeley, Berkeley, California 94720-1460, USA   Email: kpcv@berkeley.edu
,
K. Peter C. Vollhardt*
Department of Chemistry, University of California at Berkeley, Berkeley, California 94720-1460, USA   Email: kpcv@berkeley.edu
› Author Affiliations
Further Information

Publication History

Received: 23 June 2015

Accepted after revision: 07 July 2015

Publication Date:
29 July 2015 (online)


Abstract

An experimental foray into the potential of oxazoles and thiazoles to enter into CpCo-mediated [2+2+2] cycloadditions is described. α,ω-Diynes failed to engage the heterocycles productively, as illustrated by the behavior of the unique cobaltacyclopentadiene(oxazole) complex 10, the isolation and X-ray structural determination of which is recorded. Alkyne-tethered systems gave moderate yields to products resulting from [2+2+2] cycloaddition and C–H activation. The azaenol ether bridge in the cycloaddition products appears sensitive to oxidation, elimination, and rearrangement, depending on the system and reaction conditions.

Supporting Information