Rhodium-Catalyzed One-pot Chemoselective Insertion-Rearrangement-Cyclization of Azavinyl Carbenes with 2-Aminobenzyl Alcohols.

Chemoselective insertion of in situ generated α-imino rhodium carbene onto the O-H bond of 2-aminobenzyl alcohols over the N-H bond followed by [1,3]-alky shift has been successfully accomplished for the synthesis of amine tethered ketone derivatives. The resultant product was further cyclized under acidic conditions to afford biologically important 3-aminoquinolines. Successful integration of chemoselective insertion--rearrangement and cyclization in one pot offered access to various 3-aminoquinolines in a good yield.

Rhodium Catalyzed [4 + 1]-Annulation of -Acylanilines with 3-Diazoindoline-2-imines.

An efficient rhodium catalyzed [4 + 1]-annulation of -acylanilines with 3-diazoindoline-2-imines has been successfully accomplished for the synthesis of spiroindolines in good to excellent yield. The reaction occurs through formation of -ylide followed by cyclization and showed good tolerance to various functional groups. Gram-scale synthesis, diastereoselective construction of tetrasubstituted indoline, synthesis of spirooxindole, and isolation of potential intermediates have also been demonstrated.

Rhodium-Catalyzed [4 + 2]-Annulation of -Acylanilines with -Sulfonyl-1,2,3-triazoles: Synthesis of 3-Aminoquinolines.

Efficient synthesis of 3-aminoquinolines has been demonstrated from readily accessible -sulfonyl-1,2,3-triazoles and -acylaniline derivatives. This transformation involves the generation of C-C and C-N bonds through insertion of rhodium azavinyl carbenoid into a N-H bond followed by cyclization and aromatization. The important features include good functional group tolerance, synthesis of indoloquinoline, and isolation of N-H-inserted product, a potential intermediate.

Synthesis of Dihydro-3,1-benzoxazine Derivatives from 1,3-Amino Alcohols and -Sulfonyl-1,2,3-triazole.

An efficient rhodium-catalyzed synthesis of dihydro-3,1-benzoxazine derivatives has been accomplished from aniline-derived 1,3-amino alcohols and -sulfonyl-1,2,3-triazole. The developed reaction demonstrates the new reactivity of azavinyl carbenes and allows access to diverse substituted dihydro-3,1-benzoxazines in good yields. Importantly, the reaction was readily extended to diols and could be used for selective protection of amino alcohols with -sulfonyl-1,2,3-triazole as the protecting reagent.

1,2,3-Triazole and Its Analogues: New Surrogates for Diazo Compounds.

Readily accessible and shelf-stable 1,2,3-triazole and its analogues such as pyridotriazole, triazoloindole, benzotriazole, and thiadiazole exist in equilibrium with their ring-opened isomers, , diazo compounds. These ring-opened isomers could be trapped by various metal catalysts (e.g.