We have developed a protocol for palladium-catalyzed decarboxylative [4 + 3] cycloaddition reactions between 4-vinyl benzoxazinanones and azomethine imines to generate moderate to good yields of structurally diverse 1,2,4-benzotriazepines bearing two stereogenic centers with good to excellent stereoselectivities. This protocol not only addresses the challenge of asymmetrically constructing compounds with a 1,2,4-benzotriazepine skeleton but also demonstrates the utility of decarboxylative cycloadditions for the synthesis of enantioenriched polycyclic compounds.

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A base promoted sequential [4 + 2]- and [1 + 2]-annulation of 2-hydroxychalcones or 2-tosylaminochalcones with prop-2-ynylsulfonium salts was developed.

The [4+3] annulation reaction of crotonate-derived sulfur ylides with benzylidenepyrazolones using K2CO3 as the base is reported. The ready availability of starting materials and the simple cyclization procedure make this approach suitable for the preparation of a diverse array of 4,7-dihydro-1H-oxepino[2,3-c]pyrazoles in good to excellent yields.

A simple solvent-free method for the regioselective synthesis of pyrazoline derivatives via the annulation reactions of α-cyanoα,β-unsaturated ketones and β-carboxylic ester-α,β-unsaturated ketone with Huisgen zwitterions was developed. Interestingly, the reaction substrate is identified as a critical factor to control the final products. This method features simplicity, high efficiency, environmentally benign, and broad substrate scope. The gram scale applicability also points towards its possible implementation in industrial use.