Oxidative oxy-cyclization of 2-alkynylbenzamide enabled by TBAB/Oxone: switchable synthesis of isocoumarin-1-imines and isobenzofuran-1-imine.

A TBAB-catalyzed oxidative 6-endo-dig oxy-cyclization of 2-alkynylbenzamide is described herein for the synthesis of isocoumarin-1-imines. The transformation proceeds regioselectively and provides the final products with high efficiency and a broad reaction scope. Interestingly, an array of isobenzofuran-1-imines is also achieved under standard conditions when N-phenyl 2-trimethylsilylethynylbenzamides are used as substrates. Mechanism studies show that 3-bromomethenisobenzofuran-1-imine is a pivotal intermediate, which goes through C-O bond migration and debromination to offer the final isocoumarin-1-imines.

One-pot regioselective C-H activation iodination-cyanation of 2,4-diarylquinazolines using malononitrile as a cyano source.

A one-pot cyanation of 2,4-arylquinazoline with NIS and malononitrile has been developed. The one-pot reaction includes two steps. The Rh-catalyzed selective C-H activation/iodization of 2,4-diarylquinazoline with NIS, and then Cu-catalyzed cyanation of the corresponding iodinated intermediate with malononitrile to selectively give 2-(2-cyanoaryl)-4-arylquinazolines or 2-(2,6-dicyanoaryl)-4-arylquinazolines in good to excellent yields.

The asymmetric Cu(II)-indolinylmethanol complex catalyzed Diels-Alder reaction of 2-vinylindoles with ß,γ-unsaturated α-ketoesters: an efficient route to functionalized tetrahydrocarbazoles.

An efficient asymmetric Diels-Alder reaction of 2-vinylindoles with ß,γ-unsaturated α-ketoesters has been developed for the construction of functionalized tetrahydrocarbazoles. The products were obtained in high yields (up to 96%) with good stereoselectivities (ee up to 95%, dr up to >99 : 1).