A Sydnone Cycloaddition Route to Pyrazole Boronic Esters

Abstract

From dipole to diazole! A direct and regioselective route to functionalized pyrazole boronic esters is developed that employs the cycloaddition of alkynylboronates with sydnones. Functionalization of these products by Suzuki coupling and N-deprotection processes highlight the potential synthetic utility of these species. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2007/z703767_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.