michael addition of pyrimidine and purine nucleobases to substituted as well as unsubstituted α,β-unsaturated esters efficiently proceeds in the presence of catalytic amount of zinc oxide in ionic liquid 1-butyl-3-methylimidazolium bromide (zno/[bmim]br) under microwave irradiation to afford carboacyclic nucleosides, as biologically important compounds, in good to excellent yields and in short ...

In an approach to the biologically important 6-azabicyclo[3.2.1]octane ring system, the scope of the tandem 4-exo-trig carbamoyl radical cyclization-dithiocarbamate group transfer reaction to ring-fused β-lactams is evaluated. β-Lactams fused to five-, six-, and seven-membered rings are prepared in good to excellent yield, and with moderate to complete control at the newly formed dithiocarbamat...

A direct and selective synthesis of α,β-unsaturated piperidones by a new palladium-catalyzed cascade carbonylation is described. In the presented protocol, easily available propargylic alcohols react with aliphatic amines to provide broad variety interesting heterocycles. Key success this transformation remarkable catalytic cleavage present carbon–carbon triple bond using specific catalyst 2-di...

Selective hydrogenation of the carbon-oxygen bond in α,β-unsaturated carbonyl compounds is a synthetic challenge, since C=C bond reduction is thermodynamically more favorable (35 kJ mol–1) than C=O bond reduction.[1] This problem becomes even more complicated by the presence of an aromatic substituent in such systems because of possible ring hydrogenation.[2] Moreover, the transformation of uns...

Transition-metal-catalyzed [4+2] heteroannulation of α,β-unsaturated oximes and their derivatives with alkynes has been developed into a powerful strategy for the synthesis pyridines. It nevertheless lacks regioselectivity when unsymmetrically substituted are used. We report herein unprecedented polysubstituted pyridines by formal [5+1] two readily accessible building blocks. A copper-catalyzed...

We report a one-pot formation of 2,4-diolefinic or 2,4,6-triolefinic monocarboxylic acids, R-(CH 000000000000 000000000000 000000000000 111111111111 000000000000 111111111111 000000000000 000000000000 000000000000 CH)2or3-COOH, by decarboxylative condensation of an optionally α,β-unsaturated aldehyde with glutaconic acid, HOOC-CH2-CHCH-COOH as straight chain C4-extender. The reaction is broadly...