We have demonstrated for the first time that carboxylic acids are able to catalyze the direct hydroboration of various terminal and internal alkynes with pinacolborane without using any metal catalysts. This unprecedented catalytic hydroboration exhibits a broad functional groups compatibility, giving the corresponding alkenyl diboronates and monoboronates in good to high yields with exclusive regio- and stereoselectivities.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/ol502285s | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Hydroboration of Terminal Alkynes Catalyzed by a Mn(I) Alkyl PCP Pincer Complex Following Two Diverging Pathways.
ACS Catal
August 2024
Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9/163-AC, Wien A-1060, Austria.
A stereo- and regioselective Mn(I)-catalyzed hydroboration of terminal alkynes with pinacolborane (HBPin) is described. The hydroboration reaction is highly -selective in the case of aryl alkynes and -selective in the case of aliphatic alkynes. The reaction requires no additives or solvents and proceeds with a catalyst loading of 1 mol % at 50-70 °C.
View Article and Find Full Text PDFRegioselective Hydroboration of Unsymmetrical Internal Alkynes Catalyzed by a Cobalt Pincer-NHC Complex.
Org Lett
July 2024
Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India.
Highly regioselective hydroboration of unsymmetrical internal alkynes remains a significant challenge for synthesizing valuable alkenylboronate esters. Herein, we describe an easily synthesizable pincer NHC-based Co complex as a catalyst for the -α selective hydroboration of unactivated internal alkynes and the -β selective hydroboration of activated internal alkynes with pinacolborane. The reaction showcases high chemo-, regio-, and stereoselectivity, and the catalyst displays high efficiency and very low loading under base-free reaction conditions.
View Article and Find Full Text PDFTandem manganese catalysis for the chemo-, regio-, and stereoselective hydroboration of terminal alkynes: precatalyst activation as a key to enhanced chemoselectivity.
RSC Adv
February 2024
Department of Chemistry and Biochemistry, University of California 5200 North Lake Road 95343 Merced California USA
The manganese(ii) complex [Mn(PNP)Cl] (PNP = 2,6-bis(diisopropylphosphinomethyl)pyridine) was found to catalyze the stereo- and regioselective hydroboration of terminal alkynes employing HBPin (pinacolborane). In the absence of activators, mixtures of alkynylboronate and -alkenylboronate esters were formed, whereas when NaHBEt was employed as the activator, -alkenylboronate esters were exclusively accessed. Mechanistic studies revealed a tandem C-H borylation/semihydrogenation pathway accounting for the formation of the products.
View Article and Find Full Text PDFReactions of an Osmium-Hexahydride Complex with 2-Butyne and 3-Hexyne and Their Performance in the Migratory Hydroboration of Aliphatic Internal Alkynes.
Organometallics
September 2022
Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain.
Reactions of the hexahydride OsH(PPr) () with 2-butyne and 3-hexyne and the behavior of the resulting species toward pinacolborane (pinBH) have been investigated in the search for new hydroboration processes. Complex reacts with 2-butyne to give 1-butene and the osmacyclopropene OsH(η-CMe)(PPr) (). In toluene, at 80 °C, the coordinated hydrocarbon isomerizes into a η-butenediyl form to afford OsH(η-CHCHCHCH)(PPr) ().
View Article and Find Full Text PDFTransition Metal-Free Regio- and Stereo-Selective trans Hydroboration of 1,3-Diynes: A Phosphine-Catalyzed Access to (E)-1-Boryl-1,3-Enynes.
Chemistry
November 2022
Department of Chemistry, Virginia Tech, Blacksburg, Virginia, United States.
We report a transition metal-free, regio- and stereo-selective, phosphine-catalyzed method for the trans hydroboration of 1,3-diynes with pinacolborane that affords (E)-1-boryl-1,3-enynes. The reaction proceeds with excellent selectivity for boron addition to the external carbon of the 1,3-diyne framework as unambiguously established by NMR and X-ray crystallographic studies. The reaction displays a broad substrate scope including unsymmetrical diynes to generate products in high yield (up to 95 %).
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!