Related Experiment Video
Updated: Aug 6, 2026
08:56
Synthesis of a Borylated Ibuprofen Derivative Through Suzuki Cross-Coupling and Alkene Boracarboxylation Reactions
Published on: November 30, 2022
Diazoborane-Promoted Boron Insertion into Olefinic C-H Bonds
Chonghe Zhang1, Christopher C Cummins1, Robert J Gilliard1
1Department of Chemistry, Massachusetts Institute of Technology, Cambridge02139, Massachusetts, United States.
Journal of the American Chemical Society
|July 22, 2026
Summary
Researchers developed a new borylation method using diazoboranes. This novel reaction inserts boron into olefinic C-H bonds, offering a versatile synthetic strategy for organoboron compounds.
Area of Science:
- Synthetic Chemistry
- Organometallic Chemistry
- Catalysis
Background:
- Organoboron compounds are crucial intermediates in organic synthesis and materials science.
- Developing new borylation strategies is essential for accessing diverse organoboron structures.
- Existing methods often involve addition or substitution reactions.
Purpose of the Study:
- To introduce a novel borylation reaction mediated by diazoboranes.
- To investigate the mechanism and scope of this new C-H functionalization method.
Main Methods:
- Utilized diazoboranes (RLBN2) as borylene precursors.
- Performed C-H insertion reactions into various olefins.
- Conducted detailed mechanistic studies, including stereochemical analysis.
Main Results:
- Diazoboranes mediate direct insertion into olefinic C-H bonds.
- The reaction exhibits broad substrate scope, including diverse olefin types.
- High stereoselectivity for the E isomer is observed in most cases (>99%).
- Specific substrates like acrylonitrile yield the Z isomer with high selectivity (>99%).
Conclusions:
- Diazoborane-mediated borylation represents a new and efficient route to organoboron compounds.
- The stereochemical outcome is governed by a balance of electronic and steric factors.
- This method expands the toolkit for C-H functionalization and organoboron synthesis.
More Related Videos
Related Concept Videos
03:08Hydroboration-Oxidation of Alkenes
In addition to the oxymercuration–demercuration method, which converts the alkenes to alcohols with Markovnikov orientation, a complementary hydroboration-oxidation method yields the anti-Markovnikov product. The hydroboration reaction, discovered in 1959 by H.C. Brown, involves the addition of a B–H bond of borane to an alkene giving an organoborane intermediate. The oxidation of this intermediate with basic hydrogen peroxide forms an alcohol.
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
Introduction
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.
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.
02:36Regioselectivity and Stereochemistry of Hydroboration
A significant aspect of hydroboration–oxidation is the regio- and stereochemical outcome of the reaction.
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.
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.
01:14Electrophilic 1,2- and 1,4-Addition of X2 to 1,3-Butadiene
Electrophilic addition of halogens to alkenes proceeds via a cyclic halonium ion to form a 1,2-dihalide or a vicinal dihalide.
02:46Halogenation of Alkenes
Halogenation is the addition of chlorine or bromine across the double bond in an alkene to yield a vicinal dihalide. The reaction occurs in the presence of inert and non-nucleophilic solvents, such as methylene chloride, chloroform, or carbon tetrachloride.
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
02:15Preparation of Alcohols via Addition Reactions
Overview
The acid-catalyzed addition of water to the double bond of alkenes is a large-scale industrial method used to synthesize low-molecular-weight alcohols. An acidic atmosphere is required to allow the hydrogen in the water molecule to act as an electrophile and attack the double bond in an alkene. The addition of a proton to the double bond creates a carbocation intermediate. The proton preferentially bonds to the less substituted end of the double bond to create a more stable carbocation...
The acid-catalyzed addition of water to the double bond of alkenes is a large-scale industrial method used to synthesize low-molecular-weight alcohols. An acidic atmosphere is required to allow the hydrogen in the water molecule to act as an electrophile and attack the double bond in an alkene. The addition of a proton to the double bond creates a carbocation intermediate. The proton preferentially bonds to the less substituted end of the double bond to create a more stable carbocation...