A Combination of Furfuryl Cation Induced Three-Component Reactions and Photocatalyst-Free Photoisomerization To Construct Complex Triazoles.

A novel stereospecific synthesis of ( Z)- and ( E)-β-triazole-acrylates by the combined use of a multicomponent reaction and photocatalyst-free photoisomerization is presented. The former can be regarded as a furfuryl cation induced formal [3 + 2]-cycloaddition/ring-opening/esterification domino sequence, which provides fast access to a variety of structurally diverse ( Z)-β-triazole-acrylates. The products were further photoisomerized to ( E)-configuration by UV irradiation. This efficient strategy was utilized in the concise synthesis of histone deacetylase inhibtor NSC746457 in high yield.