A Study of the Scope and Regioselectivity of the Ruthenium-Catalyzed [3 + 2]-Cycloaddition of Azides with Internal Alkynes
作者:Max M. Majireck、Steven M. Weinreb
DOI:10.1021/jo061688m
日期:2006.10.1
[3 + 2]-Cycloadditions of alkyl azides with various unsymmetrical internal alkynes in the presence of Cp*RuCl(PPh3)(2) as catalyst in refluxing benzene have been examined, leading to 1,4,5-trisubstituted-1,2,3-triazoles. Whereas alkyl phenyl and dialkyl acetylenes undergo cycloadditions to afford mixtures of regioisomeric 1,2,3-triazoles, acyl-substituted internal alkynes react with complete regioselectivity. In addition, propargyl alcohols and propargyl amines were found to react with azides to afford single regioisomeric products.
A direct route to triazole boronic esters and their application in the synthesis of small molecule arrays
Alkynylboronates represent useful substrates for the direct synthesis of triazole boronic esters by their thermal cycloaddition with azides. A telescoped cycloaddition-cross-coupling protocol is reported and its employment in the synthesis of a small triazole array is disclosed. (C) 2009 Elsevier Ltd. All rights reserved.