Related Experiment Video
Updated: Jun 12, 2025
Synthesis of a Borylated Ibuprofen Derivative Through Suzuki Cross-Coupling and Alkene Boracarboxylation Reactions
Published on: November 30, 2022
Mechanistic Study on Copper- and Silver-Catalyzed Hydroboration of Internal Alkynes: A DFT Study
Ivanna G R Juliani Costa1, Patrick R Batista2, Marcelo T de Oliveira3,4,5
1Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes, 748, São Paulo, São Paulo 05508-000, Brazil.
None:
The present study employs DFT calculations and the independent gradient model (IGM) approach to investigate a mechanism study of the hydroboration reaction of internal alkynes catalyzed by Ag-(I)-IMes and Cu-(I)-IMes complexes. A detailed analysis of the mechanism's steps revealed that Cu-(I)-IMes exhibits superior efficiency, showing a more favorable energy pathway than Ag-(I)-IMes. The IGM method was crucial for quantifying molecular interactions, highlighting essential differences in binding forces between catalysts and substrates throughout the catalytic steps. For Cu-(I)-IMes, the migratory insertion step (TS1) demonstrated a barrier 2.5 times lower than its Ag-(I)-IMes counterpart. Additionally, the protonation step (TS2) exhibited lower energy for Cu-(I)-IMes compared to Ag-(I)-IMes, indicating a more efficient formation of the desired β-product. The results also suggest that Cu-(I)-IMes operates on a more efficient pathway, with lower energy for the catalytic cycle. These findings, coupled with detailed analyses of molecular interactions using the IGM method, provide an enhanced understanding of the reaction mechanism, highlighting the promising efficacy of Cu-(I)-IMes as a catalyst in hydroboration reactions.
More Related Videos
09:54Chemoselective Preparation of 1-Iodoalkynes, 1,2-Diiodoalkenes, and 1,1,2-Triiodoalkenes Based on the Oxidative Iodination of Terminal Alkynes
Published on: September 12, 2018
09:35Preparation of a Corannulene-functionalized Hexahelicene by CopperI-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units
Published on: September 18, 2016
Related Concept Videos
02:47Alkynes 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.
02:40Alkynes to Aldehydes and Ketones: Acid-Catalyzed Hydration
Analogous to alkenes, alkynes also undergo acid-catalyzed hydration. While the addition of water to an alkene gives an alcohol, hydration of alkynes produces different products such as aldehydes and ketones.
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
02:36Regioselectivity 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...
03:08Hydroboration-Oxidation of Alkenes
02:42Acidity of 1-Alkynes
The acidic strength of hydrocarbons follows the order: Alkynes > Alkenes > Alkanes. The strength of an acid is commonly expressed in units of pKa — the lower the pKa, the stronger the acid. Among the hydrocarbons, terminal alkynes have lower pKa values and are, therefore, more acidic. For example, the pKa values for ethane, ethene, and acetylene are 51, 44, and 25, respectively, as shown here.