1
|
Paul A, Sengupta A, Sarkar B, Yadav S. Acetoxy Group-Directed Regioselective C2 Alkenylation of Indoles via Pd-Ag Bimetallic Catalysis. J Org Chem 2023; 88:14423-14434. [PMID: 37794781 DOI: 10.1021/acs.joc.3c01442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/06/2023]
Abstract
Regioselective C-H functionalizations of indoles reported to date with directing groups at C3 mainly rely on functional groups that are linked to the indole via C-C bonds. However, groups that are linked to the indole core by C-X linkages are also attractive due to the possibility of further modifications of the C-X bond. Herein, we report a 3-acetoxy directing group for the regioselective C2 alkenylation of indoles via a C-H activation-based, cross-dehydrogenative, oxidative Heck-type reaction. The reaction is catalyzed by Pd(II) and Ag(I) with stoichiometric Cu(II) as the oxidant and provides the 2-alkenylated indoles in yields of 52-84%. The reaction conditions are compatible with several functional groups at different positions as well as different N-protecting groups or free NH groups on the indole core. With respect to the alkene coupling partners, the reactions are successful with acrylates, vinyl sulfates, and phosphates. Specifically designed experiments, as well as density functional theory (DFT) computational studies, reveal that a heterodinuclear [Pd(μ-OAc)3Ag] bimetallic species is the actual catalyst responsible for the C-H alkenylation. A mechanistic path involving this catalytic species was also found to be favorable over other possible pathways for explaining the observed regioselectivity through DFT studies.
Collapse
Affiliation(s)
- Aditya Paul
- Department of Chemistry and Chemical Biology, Indian Institute of Technology (ISM) Dhanbad, Jharkhand 826004, India
| | - Arunava Sengupta
- Department of Chemistry and Chemical Biology, Indian Institute of Technology (ISM) Dhanbad, Jharkhand 826004, India
| | - Bijan Sarkar
- Department of Chemistry and Chemical Biology, Indian Institute of Technology (ISM) Dhanbad, Jharkhand 826004, India
| | - Somnath Yadav
- Department of Chemistry and Chemical Biology, Indian Institute of Technology (ISM) Dhanbad, Jharkhand 826004, India
| |
Collapse
|
2
|
Zhang C, Shang Z, Li R, Xu X. DFT study on the mechanism of selectively oxidative C(sp2)–H/C(sp3)–H cross-coupling of benzamides with amides by nickel catalyst: Oxidant-controlled regioselectivity. Tetrahedron Lett 2022. [DOI: 10.1016/j.tetlet.2022.154073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
3
|
Liu S, Wang Q, Huang F, Wang W, Yang C, Liu J, Chen D. Insight into the mechanism of the arylation of arenes via norbornene relay palladation through meta- to para-selectivity. Org Chem Front 2022. [DOI: 10.1039/d1qo01500a] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A theoretical insight was shown into the origin of site-selectivity in the arylation of arenes by a norbornene relay palladation through meta- to para-selectivity.
Collapse
Affiliation(s)
- Shengnan Liu
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Institute of Molecular and Nano Science, Shandong Normal University, Jinan 250014, P. R. China
| | - Qiong Wang
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Institute of Molecular and Nano Science, Shandong Normal University, Jinan 250014, P. R. China
| | - Fang Huang
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Institute of Molecular and Nano Science, Shandong Normal University, Jinan 250014, P. R. China
| | - Wenjuan Wang
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Institute of Molecular and Nano Science, Shandong Normal University, Jinan 250014, P. R. China
| | - Chong Yang
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Institute of Molecular and Nano Science, Shandong Normal University, Jinan 250014, P. R. China
| | - Jianbiao Liu
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Institute of Molecular and Nano Science, Shandong Normal University, Jinan 250014, P. R. China
| | - Dezhan Chen
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Institute of Molecular and Nano Science, Shandong Normal University, Jinan 250014, P. R. China
| |
Collapse
|