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A nickel(0)-catalyzed intermolecular [3+2] cycloaddition of bis(alkylidenecyclopropanes) with diazenes such as diethyl or diisopropyl azodicarboxylate gave pyrazolidine-1,2-dicarboxylates in moderate to good yields (61–72%). [ABSTRACT FROM AUTHOR]

Acetylenic ester promoted ring opening of dienyl-thiazolidin- 4-ones and subsequent electrocyclization affords 5-phenyl-6-aryl pyridine-2-carboxylates in good to excellent yields. [ABSTRACT FROM AUTHOR]

Tandem aza-Michael addition of 3-amino-2-azetidinones with acetylenic esters and subsequent intramolecular amidic ring opening of the initially formed azetidin-3-ylaminoprop- or -but-2-enoic ester is described. The reaction provides a facile route for the formation of functionalized 4-oxo-4,5-dihydro-1H-pyrroles in good yields. [ABSTRACT FROM AUTHOR]

Highly diastereo- and π-facially selective imino Diels–Alder cycloadditions of 3-allylideneamino-2-azetidinones having stereocentres at its α- and β-positions, with symmetrical dienophiles leading to the formation of biologically potent (2-oxo-4-styrylazetidin-3-yl)–pyridine hybrids have been reported. [ABSTRACT FROM AUTHOR]