All-carbon tetrasubstituted olefins have been found in numerous biologically important compounds and organic materials. However, regio- and stereocontrolled construction of this structural motif still constitutes a significant synthetic challenge. Here, we show that a modular and regioselective synthesis of all-carbon tetrasubstituted olefins can be realized via alkenyl halide- or triflate-mediated palladium/norbornene catalysis, which is enabled by a modified norbornene containing a C2 amide moiety. This new norbornene co-catalyst effectively suppressed undesired cyclopropanation pathways, which have previously been a main obstacle for developing such reactions. Diverse cyclic and acyclic alkenyl bromides or triflates with a wide range of functional groups can be employed as substrates. Various substituents can be introduced at the alkene C1 and C2 positions regioselectively simply by changing the coupling partners. Initial mechanistic studies provide insights on the rate-limiting step as well as the structure of the actual active ligand in this system.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7098644 | PMC |
| http://dx.doi.org/10.1038/s41557-019-0358-y | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Diversity-oriented synthesis of stereodefined tetrasubstituted alkenes via a modular alkyne gem-addition strategy.
Nat Commun
January 2025
School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, China.
Stereocontrolled construction of tetrasubstituted olefins has been an attractive issue yet remains challenging for synthetic chemists. In this manuscript, alkynyl selenides, when treated with ArBCl, are subject to an exclusive 1,1-carboboration, affording tetrasubstituted alkenes with excellent levels of E-selectivity. Detailed mechanistic studies, supported by DFT calculations, elucidates the role of selenium in this 1,1-addition process.
View Article and Find Full Text PDFAmide-Directed Highly Enantioselective Hydrogenation of Diverse Acyclic Multisubstituted Alkenes Under Mild Conditions.
Angew Chem Int Ed Engl
January 2025
Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing, 100084, China.
Enantioselective hydrogenation of tetrasubstituted alkenes to form 1,2-contiguous stereocenters is a particularly appealing but highly challenging transformation in asymmetric catalysis. Despite the notable progress achieved in enantioselective hydrogenation over the past decades, enantioselective hydrogenation of all-carbon tetrasubstituted alkenes containing multiple alkyl groups remains an unsolved challenge. Here, we report a rhodium-catalyzed highly diastereo- and enantioselective hydrogenation of diverse acyclic multisubstituted alkenes under mild conditions.
View Article and Find Full Text PDFStereoselective Ring-Opening Reaction of α-Fluorinated Oxetanes: A Practical and Theoretical Investigation.
J Org Chem
December 2024
Université de Caen Normandie, ENSICAEN, CNRS, LCMT, Normandie University, 6 Bd. du Maréchal Juin, Caen 14050, France.
The ring-opening reaction of fluorinated oxetanes by halides, including alkylidene oxetanes and spirocyclic oxetanes, was highly stereoselective and directed by the presence of a fluorine atom. This reaction allowed a stereoselective preparation of tetrasubstituted alkenes and substituted pyrrolidines containing all-carbon quaternary centers. Theoretical calculations were performed to shed light on experimentally observed regioselectivity in the opening of oxetane derivatives.
View Article and Find Full Text PDFPalladium-catalyzed -alkynylarylation of internal alkynes: rapid access to all-carbon tetrasubstituted alkenes.
Chem Commun (Camb)
August 2024
School of Chemistry and Chemical Engineering, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China.
Herein, a straightforward method for rapid access to all-carbon tertrasubstituted alkenes bearing alkyl, aryl and alkynyl groups is established palladium-catalyzed three-component cross-coupling reaction of internal alkynes, haloalkynes and arylboronic acids. This protocol is characterized by a broad substrate scope and excellent chemo- and regioselectivities. The dual beneficial roles of silver salts in activating haloalkynes and inhibiting bromoalkynylation have been demonstrated by serving as both the Lewis acid and halide scavenger.
View Article and Find Full Text PDFStereoselective benzylic C(sp)-H alkenylation enabled by metallaphotoredox catalysis.
Chem Sci
August 2024
State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 China.
Article Synopsis
- The study focuses on selective activation of benzylic C(sp)-H bonds for creating complex organic compounds, highlighting the challenges associated with selecting among similar C-H bonds.
- A site- and stereoselective method is introduced using metallaphotoredox catalysis, allowing for the production of various tri- and tetrasubstituted olefins from complex substrates with multiple benzylic sites.
- The technique demonstrates exceptional site-selectivity and can be scaled up, making it a practical approach for synthesizing enantioenriched products and functionalizing intricate structures.
Want 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!