Multicomponent 1,3-Bifunctionalization of Donor–Acceptor Cyclopropanes with Arenes and Nitrosoarenes

Metal-Free Sequential C(sp2)-H/OH and C(sp3)-H Aminations of Nitrosoarenes and N-Heterocycles to Ring-Fused Imidazoles

Hydrogen bond assisted ortho-selective C(sp²)-H amination of nitrosoarenes and subsequent α-C(sp³)-H functionalization of aliphatic amines is achieved under metal-free conditions. The annulation of nitrosoarenes and 2-hydroxy-C-nitroso compounds with N-heterocycles provides a facile excess to a wide range of biologically relevant ring-fused benzimidazoles and structurally novel polycyclic imidazoles, respectively. Nucleophilic aromatic hydrogen substitution (S_NArH) was found to be preferred over classical S_NAr reaction during the C(sp²)-H amination of halogenated nitrosoarenes.

Ring-Opening 1,3-Halochalcogenation of Cyclopropane Dicarboxylates

Donor-acceptor cyclopropanes with two geminal carboxylic esters are reacted with chalcogenyl chlorides and bromides to afford ring-opened products bearing the halogen atoms in the 1-position, adjacent to the donor, and the chalcogenyl residue in the 3-position next to the two acceptor groups. A variety of different donors (e.g., aryl, N, and O) are used. The stereospecificity of the reaction is demonstrated by using a chiral starting material.