Cu(I)-azidopyrrolo[3,2-d]pyrimidine Catalyzed Glaser-Hay Reaction under Mild Conditions.

The limitation of the CuAAC "click" reaction with a 2-azidopyridine substrate, owing to its equilibrium with a tetrazole isomer, is exploited herein for its utility in the Glaser-Hay reaction. A catalytic combination of a 2-azidopyridine analogue, 4-azido-5H-pyrrolo[3,2-d]pyrimidine, and CuI afforded homocoupled products of terminal alkynes, without any trace of triazole product, under mild conditions with a broad substrate scope. Emphasis on carbohydrate-based substrates appended to a propargylic group led to 1,3-diynes in good to excellent yields.

Dienaminodioate based multicomponent reactions with post-benzylic oxidative transformations mediated by DDQ.

Multicomponent reactions (MCRs) using dienaminodioate with post-benzylic oxidative transformation mediated by DDQ that afforded a diverse array of products are described. An unprecedented rearrangement of 1,2-dihydropyridines (1,2-DHPs), 3CR products, to 2-pyridones in good yields with a broad substrate scope by DDQ-mediated benzylic oxidation via a pyridinium intermediate is reported. Treatment of the pyridinium intermediate with tert-butyl isocyanide afforded isomerized 1,2-DHPs, analogous to Ritter amides. Further diversification using 3CR products bearing a benzylic group, predictably, promoted the synthesis of 2-pyridone with a benzylideneamine group and a benzo[d]oxazole appended biaryl group by DDQ. A formal 1,6-reduction product from 2-pyridone in the presence of NaBH4 is also observed.