Kinetically unstable nitrones are generated from gold-catalyzed reactions of 1,6-enynes with N-hydroxyanilines, and subsequently trapped by tethered alkenes to furnish [2+2+1]-annulations. Our experimental data reveal that such nitrones arise from atypical N-attack chemoselectivity that is triggered by tethered alkenes to facilitate the key protodeauration reaction.

Regiocontrolled hydrations of 1-aryl-3-en-1-ynes have been accomplished with IPrAuOTf and PtCl2/CO to yield 3-en-1-ones and 2-en-1-ones efficiently; our experimental data indicates that the sizes of catalysts play an important role.

This work reports new (4 + 2)-annulations of α-alkyl vinylgold carbenes with benzisoxazoles to afford 3,4-dihydroquinoline derivatives with high anti-stereoselectivity.