Modular preassembly of azaxylylene photoprecursors, halogen-substituted in the aromatic ring, their intramolecular [4 + 4] or [4 + 2] cycloadditions to tethered unsaturated pendants, and subsequent postphotochemical capstone modification of the primary photoproducts via Suzuki coupling provides rapid access to diverse biaryls of unprecedented topology. This synthetic sequence allows for rapid g...

Copper-catalyzed (click chemistry) or thermal 1,3-dipolar cycloadditions of molecular or polymeric azido-siloxanes with a broad range of alkynes (such as amino acids or carbohydrates) easily yield new conjugates that would be otherwise difficult, if not impossible, to prepare by traditional methodologies.

Intramolecular inverse electron demand cycloadditions of isatin-derived 1,2,4-triazines with acetylenic dienophiles tethered by amidations or transesterifications proceed in excellent yields to produce lactam- or lactone-fused α-carbolines. Beginning with various isatins and alkynyl dienophiles, a pilot-scale library of eighty-eight α-carbolines was prepared by using this robust methodology for...

12-Hydroxy-9(10-->20)-5aH-abeo-abieta-1(10),8(9),12(13)-triene-11,14-dione (quinone 2) served as the dienophile in numerous intermolecular Diels-Alder reactions. These cycloadditions were conducted either thermally (including microwave heating) or with Lewis acid activation. While most dienes reacted with quinone 2 in good chemical yield, others were incompatible under the experimental conditio...

DFT calculations were performed to shed light on the molecular mechanism of [3 + 2] cycloadditions of simple conjugated nitroalkenes to benzonitrile N-oxides. In particular, it was found that these processes proceed by a one-step mechanism through asynchronous transition states. According to the latest terminology, they should be considered polar but not stepwise processes.

The Rh(II)-catalyzed formal [3+2] and [3+3] cycloadditions of 1-tosyl 1,2,3-triazoles with 2H-azirines have been developed, which enable the efficient synthesis of polysubstituted 3-aminopyrroles and 1,2-dihydropyrazines, respectively. The reported [3+2] cycloaddition represents the first application of 1-sulfonyl 1,2,3-triazole as a [2C]-component in relevant cycloaddition reactions.

N-type pyrazine-based 1,4- and 1,5-disubstituted 1,2,3-triazole derivatives, showing unique aggregation-enhanced emission characteristics, were facilely prepared via Cu- and Ru-catalysed azide-alkyne cycloadditions, respectively. Thanks to their electron-deficient properties, they could readily form red-emissive charge transfer complexes with electron-donating triphenylamine in the aggregate an...

Isocyanates, isothiocyanates, and carbodiimides are effective substrates in (3 + 2) cycloadditions with donor-acceptor cyclopropanes for the synthesis of five-membered heterocycles. These reactions exhibit a broad substrate scope, high yields, and well-defined chemoselectivity. Discussed herein are the implications of Lewis acid choice on the stereochemical outcome and the reaction mechanism.

In the present perspective the advances and real possibilities of 1,3-dipolar cycloadditions as key steps in the total synthesis of virus inhibitors are described. Azides, nitrones, and azomethine ylides are the most appropriate 1,3-dipoles for the synthesis of privileged structures with the highest biological responses against viruses.

Iminium ions generated in situ via copper(I) bromide catalyzed oxidation of N-aryl amines readily undergo [4 + 2] cycloadditions with a range of dienophiles. This method involves the functionalization of both a C(sp(3))-H and a C(sp(2))-H bond and enables the rapid construction of polycyclic amines under relatively mild conditions.