Related Experiment Video
Updated: Jan 7, 2026

Synthesis of a Borylated Ibuprofen Derivative Through Suzuki Cross-Coupling and Alkene Boracarboxylation Reactions
Published on: November 30, 2022
Reaction of Diazo Compounds with Borenium Ions: C-H Bond Activation/Annulation vs 1,1-Carboboration
Xi Wang1, Xieyi Jing1, Gangfeng Tang1
1Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, Fudan University, Shanghai 200438, China.
Abstract:
In this work, we investigated the reactivity of highly electrophilic o-carboranyl-substituted borenium ions with diaryldiazomethane compounds. When the borenium center bears a small methyl substituent, C-H bond activation/annulation was observed, resulting in the formation of indazolium ions. On the other hand, for the borenium ions with larger substituents, such as Et, Cy, or Ph, 1,1-carboboration takes place on the terminal nitrogen atom of the diazo compounds, affording borylhydrazone derivatives.
Related Concept Videos
Hydroboration-Oxidation of Alkenes
Regioselectivity and Stereochemistry of Hydroboration
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.
Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
Electrophilic 1,2- and 1,4-Addition of X2 to 1,3-Butadiene
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Mechanism
Diazonium Group Substitution: –OH and –H

