Synthesis of Various Bridged Ring Systems via Rhodium-Catalyzed Bridged (3+2) Cycloadditions

Construction of Nitrogen-Containing Three-Dimensional Frameworks via Formation and Cycloaddition of endo-Cyclic Azomethine Ylide

Triggered by the reaction of an oxime ether with a rhodium carbenoid, nitrogen-containing three-dimensional frameworks were constructed from linear motifs via the intramolecular cycloaddition of endo-cyclic azomethine ylide. In this transformation, successive stereocenters containing quaternary carbons were formed, affording the corresponding tricyclic compounds in moderate-to-good yields. The utility of these products was demonstrated through several transformations.

Annulation-Triggered Denitrogenative Transformations of 2-(5-Iodo-1,2,3-triazolyl)benzoic Acids

The ability of [1,2,3]triazolobenzoxazinones to act as a source of "hidden" diazo group was discovered. These diazo precursors can be easily prepared by the intramolecular cyclization of 2-(5-iodo-1,2,3-triazolyl)benzoic acids. The Cu-catalyzed capture of the hidden diazo group allows for further functionalization through the denitrogenative pathway. The transformations proceed via the formation of either diazoimine or diazoamide intermediates. Novel routes to various anthranilamides as well as thiolated benzoxazinones were developed using the one-pot cyclization/diazo capture procedure.