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Three types of aza-bicycles, 3-azabicylo[4.1.0]heptane-6-carbaldehyde, 3-azabicylo[4.1.0]heptane-1-carbaldehyde, and 3-azabicyclo[5.1.0]octane-7-carbaldehyde, are constructed conveniently from corresponding carbene progenitors of N-allyl or N-homoallyl triazoles. Yields are modest to high. These transformations feature a key rhodium catalyzed intramolecular cyclopropanation of the pendent C–C double bond and show complete stereo specificity.

A method for convenient synthesis of N-alkyl-2-aryl-indole-3-carbaldehyde has been described. A variety of highly valuable indolyl aldehydes have been prepared through this method. Electron donating groups on both aromatic rings (anilinyl and benzyl) facilitate the formation of the desired products. A benzylic C-H insertion by rhodium carbene is the key step for this transformation.

4-N-allylarylpropylamino-1-sulfonyl triazoles are converted to structurally unique benzopyrrolizidinyl sulfonamides in a one-pot operation. Intramolecular capture of rhodium carbene with arylamino nitrogen gives rise to the formation of an ammonium ylide immediate. A [2,3]- or [1,2]-rearrangement occurs to give a 2-allylpyrrolidinyl-2-carbimine intermediate which undergoes Cu(OTf)2 catalyzed aza-Friedel-Crafts cyclization to finish a highly functionalized tricyclic system decorated with a synthetically difficult quaternary carbon center, a sulfonamide group, and an allyl segment.

A practical method for a facile entry to structurally unique ring-fused dihydroazepine has been developed using 1-sulfonyl-1,3-dienyltriazole as starting materials. Driven by ring strain release of cyclopropyl group, a rhodium-catalyzed α-imino carbenoid formation–cyclopropanation–aza-Cope rearrangement cascade takes place efficiently in a single operation. Substitution effects on yield and diastereoselectivity are also explored.

N-Aryl-N-allyl-bis-functionalized amino-1-sulfonyl-1,2,3-trizoles undergo rhodium-catalyzed cyclization reactions and subsequent hydrolytic cleavage of the sulfonyl imine to give two structurally distinct N-heterocycles, 3-indolyl aldehydes and 3-azabicyclo[3,1,0]hexyl aldehydes. The product ratio can be tuned by varying the electronic properties of the two functional groups attached to the N atom. Based on these findings, two efficient and general methods for the synthesis of highly valuable 3-indolyl aldehydes and 3-azabicyclo[3,1,0]hexyl aldehydes have been developed.

An efficient and convenient synthesis of α-allyl cyclic amidines has been achieved by applying a novel cascade reaction. Copper(I)-mediated in situ N-sulfonyl ketenimine formation from the reaction of a terminal alkyne with sulfonyl azide is followed by an intramolecular nucleophilic attack on the central carbon atom by an allylic tertiary amine, and then an aza-Claisen rearrangement takes place through a chair transition state to furnish the titled amidines with complete stereocontrol.

Three types of aza-bicycles, 3-azabicylo[4.1.0]heptane-6-carbaldehyde, 3-azabicylo[4.1.0]heptane-1-carbaldehyde, and 3-azabicyclo[5.1.0]octane-7-carbaldehyde, are constructed conveniently from corresponding carbene progenitors of N-allyl or N-homoallyl triazoles. Yields are modest to high. These transformations feature a key rhodium catalyzed intramolecular cyclopropanation of the pendent C–C double bond and show complete stereo specificity.

A practical method for a facile entry to structurally unique ring-fused dihydroazepine has been developed using 1-sulfonyl-1,3-dienyltriazole as starting materials. Driven by ring strain release of cyclopropyl group, a rhodium-catalyzed α-imino carbenoid formation–cyclopropanation–aza-Cope rearrangement cascade takes place efficiently in a single operation. Substitution effects on yield and diastereoselectivity are also explored.

A new method for the efficient synthesis of structurally unique N-heterocycle benzopyrrolizidine is developed.

The novel cascade reaction of amino enynes with azides allows the synthesis of a wide range of α-allylic amidines in high yields.