Efficient syntheses of climate relevant isoprene nitrates and (1R,5S)-(-)-myrtenol nitrate

Overcoming Challenges in O-Nitration: Selective Alcohol Nitration Deploying N,6-Dinitrosaccharin and Lewis Acid Catalysis

Nitrate esters hold pivotal roles in pharmaceuticals, energetic materials, and atmospheric processes, motivating the development of efficient synthesis routes. Here, we present a novel catalytic method for the synthesis of nitrates via the direct O-nitration of alcohols, addressing limitations of current traditional methods. Leveraging bench-stable and recoverable N,6-dinitrosaccharin reagent, our catalytic strategy employs magnesium triflate to achieve mild and selective O-nitration of alcohols, offering broad substrate scope and unprecedentedly large functional group tolerance (e.g. alkenes, alkynes, carbonyls). DFT mechanistic studies reveal a dual role of the magnesium catalyst in the activation of both the nitrating reagent and the alcohol substrate. They also unveil a barrierless proton transfer upon formation of a widely-accepted - yet elusive in solution - nitrooxonium ion intermediate. Overall, our work contributes to the development of mild, selective, and sustainable approaches to nitrates synthesis, with potential applications in drug discovery, materials science, and environmental chemistry.

Application of Cp2TiCl-Promoted Radical-Induced Cyclization: An Expeditious Access to [a]-Annelated Indoles

An efficient and novel route for assembling pyrrolo/piperido[1,2-a]indoles is portrayed involving a radical-mediated reductive epoxide opening reaction of N-tethered epoxy-indoles that trigger facile intramolecular cyclization followed by an oxidative quenching step. Capitalizing on the operational simplicity of the method involving just two steps and use of an efficient C-C bond-forming reaction, this radical-based protocol enables the modular assembly of an important class of N-fused indole derivatives with versatile functional and structural diversity.