Metal Free Domino β-Azidation/[3 + 2] Cycloaddition Reaction for the Synthesis of 1,2,3-Triazole-Fused Dihydrobenzoxazinones.

A metal free DBU catalyzed synthesis of 1,2,3-triazole-fused dihydrobenzoxazinone derivatives by tandem β-azidation/[3 + 2] cycloaddition reaction has been developed under mild conditions. The methodological studies offer a broad scope and proceed well with a wide range of alkynylated cyclohexa 2,5-dienones, giving new -triazole-fused tricyclic scaffolds.

Palladium-catalyzed regioselective domino cyclization of cyclohexadienones.

A mild and efficient Pd-catalyzed arylative domino carbocyclization of cyclohexadienone-containing 1,6-enynes is described. The reaction tolerates a variety of functionalized boronic acids to afford a cis-fused bicyclic framework containing an α,β-unsaturated ketone with excellent regio- and diastereoselectivity in good yields. The tandem process proceeds with β-arylation of propargylic ether followed by conjugate addition of a vinyl palladium intermediate and subsequent protonolysis of a palladium enolate.