Borinic Acid Catalyzed Regioselective N-Alkylation of Azoles

A method for regioselective N-alkylation of ambident, azole-type heterocycles with alkene or epoxide electrophiles is described. In the presence of diphenylborinic acid (Ph2BOH) andan amine cocatalyst, heterocyclic nucleophiles such as 1,2,3- and1,2,4-triazoles, substituted tetrazoles, and purine are activated towardselectiveN-functionalization. The scope of electrophilic partnersincludes enones, 2-vinylpyridine, phenyl vinyl sulfone, a dehydroala-nine derivative, and epoxides. Mechanistic studies, including in situ11B NMR spectroscopy and kinetic analysis, are discussed.

Automated summary

This paper describes a method for regioselective N-alkylation of various azole-type heterocycles using alkene or epoxide electrophiles. The activation of heterocyclic nucleophiles for selective N-functionalization is achieved by using diphenylborinic acid and an amine cocatalyst.