Origins of Lewis acid accelerations in nickel catalysed C–H, C–C and C–O bond cleavages

2021 ◽  
Author(s):  
Han Gao ◽  
Lingfei Hu ◽  
Yanlei Hu ◽  
Xiangying Lv ◽  
Yanbo Wu ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Transition Metal ◽  
Lewis Acid ◽  
Transition Metal Catalysis ◽  
Current Understanding ◽  
Acid Base ◽  
Metal Catalysis

The current understanding of Lewis acid effects in transition metal catalysis is generally based on the enhanced charge transfer from metal to substrate due to the formation of Lewis acid-base...

scholarly journals Primary Alcohols via Nickel Pentacarboxycyclopentadienyl Diamide–Catalyzed Hydrosilylation of Terminal Epoxides

2019 ◽  
Author(s):  
Keri Steiniger ◽  
Tristan Lambert
Keyword(s):  
Transition Metal ◽  
Lewis Acid ◽  
Nickel Complex ◽  
Room Temperature ◽  
Transition Metal Catalysis ◽  
Primary Alcohols ◽  
Metal Catalysis

The efficient and regioselective hydrosilylation of epoxides co-catalyzed by a pentacarboxycyclopentadienyl (PCCP) diamide nickel complex and Lewis acid is reported. This method allows for the reductive opening of terminal, monosubstituted epoxides to form unbranched, primary alcohols. A screen of diamide PCCP ligands revealed a correlation of steric demand and regioselectivity, with smaller ligands being optimal, while the addition of Lewis acid enabled efficient reactions at room temperature. A range of substrates including both terminal and non-terminal epoxides are shown to work, and a mechanistic rationale is provided. This work represents the first use of a PCCP derivative as a ligand for transition metal catalysis.

scholarly journals Dialkylation of Indoles with Trichloroacetimidates to Access 3,3-Disubstituted Indolenines

Molecules ◽  
2019 ◽  
Vol 24 (22) ◽  
pp. 4143
Author(s):  
Tamie Suzuki ◽  
Nilamber A. Mate ◽  
Arijit A. Adhikari ◽  
John D. Chisholm
Keyword(s):  
Natural Products ◽  
Transition Metal ◽  
Small Molecule ◽  
Lewis Acid ◽  
Medicinal Chemistry ◽  
Transition Metal Catalysis ◽  
Metal Catalysis ◽  
Rapid Access ◽  
Privileged Scaffolds

2-Substituted indoles may be directly transformed to 3,3-dialkyl indolenines with trichloroacetimidate electrophiles and the Lewis acid TMSOTf. These reactions provide rapid access to complex indolenines which are present in a variety of complex natural products and medicinally relevant small molecule structures. This method provides an alternative to the use of transition metal catalysis. The indolenines are readily transformed into spiroindoline systems which are privileged scaffolds in medicinal chemistry.

Potassium tris(triflyl)methide (KCTf3): a broadly applicable promoter for cationic metal catalysis

2015 ◽  
Vol 51 (72) ◽  
pp. 13740-13743 ◽  
Author(s):  
Junbin Han ◽  
Zhichao Lu ◽  
Weibo Wang ◽  
Gerald B. Hammond ◽  
Bo Xu
Keyword(s):  
Transition Metal ◽  
Lewis Acid ◽  
Acid Catalysis ◽  
Wide Spectrum ◽  
Reaction Rates ◽  
Transition Metal Catalysis ◽  
Neutral Salt ◽  
Metal Catalysis ◽  
Catalyzed Reactions ◽  
Metal Catalyzed

KCTf3 enhanced the reaction rates and the chemical yields of a wide spectrum of cationic metal catalyzed reactions in consistent and significant manner. These reactions include traditional Lewis acid catalysis and transition metal catalysis. KCTf3 is an easily handled neutral salt that is commercially available.

Synthesis of N-Heterocycles via Transition-Metal-Catalyzed Tandem Addition/Cyclization of a Nitrile

Synthesis ◽  
2020 ◽  
Vol 52 (06) ◽  
pp. 819-833 ◽  
Author(s):  
Jen-Chieh Hsieh ◽  
Haw-Lih Su
Keyword(s):  
Transition Metal ◽  
Lewis Acid ◽  
Nucleophilic Addition ◽  
Radical Addition ◽  
Transition Metal Catalysis ◽  
Late Transition Metal ◽  
Metal Catalysis ◽  
Transition Metal Catalyzed ◽  
Late Transition ◽  
Metal Catalyzed

The diverse methodologies to synthesize N-heterocycles through transition-metal-catalyzed cascade addition/cyclization of a nitrile are discussed in this review. Aspects relating to three types of transition-metal-catalyzed addition of a nitrile with subsequent cyclization include (1) a transition-metal acting as a Lewis acid to accelerate the nucleophilic addition of a nitrile, (2) the late-transition-metal-catalyzed 1,2-insertion of a nitrile, and (3) an in situ generated radical by transition-metal catalysis to implement a radical addition/cyclization tandem reaction. Applications for the synthesis of natural alkaloids, their derivatives, and some bioactive compounds are also summarized herein.1 Introduction2 Nucleophilic Addition of a Nitrile Accelerated by a Lewis Acid2.1 Late-Transition-Metal Catalysis2.2 Early-Transition-Metal Catalysis2.3 Lanthanide-Metal Catalysis2.4 Cyclization from N-Arylnitriliums3 Transition-Metal-Catalyzed Insertion of a Nitrile4 Transition-Metal-Catalyzed Radical Addition of a Nitrile5 Conclusions

scholarly journals Primary Alcohols via Nickel Pentacarboxycyclopentadienyl Diamide–Catalyzed Hydrosilylation of Terminal Epoxides

2019 ◽  
Author(s):  
Keri Steiniger ◽  
Tristan Lambert
Keyword(s):  
Transition Metal ◽  
Lewis Acid ◽  
Nickel Complex ◽  
Room Temperature ◽  
Transition Metal Catalysis ◽  
Primary Alcohols ◽  
Metal Catalysis

The efficient and regioselective hydrosilylation of epoxides co-catalyzed by a pentacarboxycyclopentadienyl (PCCP) diamide nickel complex and Lewis acid is reported. This method allows for the reductive opening of terminal, monosubstituted epoxides to form unbranched, primary alcohols. A screen of diamide PCCP ligands revealed a correlation of steric demand and regioselectivity, with smaller ligands being optimal, while the addition of Lewis acid enabled efficient reactions at room temperature. A range of substrates including both terminal and non-terminal epoxides are shown to work, and a mechanistic rationale is provided. This work represents the first use of a PCCP derivative as a ligand for transition metal catalysis.

Carbon‐Sulfur Bond Constructions: From Transition‐Metal Catalysis to Sustainable Catalysis

2021 ◽  
Author(s):  
Pratheepkumar Annamalai ◽  
Ke‐Chien Liu ◽  
Satpal Singh Badsara ◽  
Chin‐Fa Lee
Keyword(s):  
Transition Metal ◽  
Transition Metal Catalysis ◽  
Metal Catalysis ◽  
Sulfur Bond

An electrochemical perspective on the roles of ligands in the merger of transition-metal catalysis and electrochemistry

2020 ◽  
Author(s):  
Ke-Yin Ye ◽  
Jun-Song Zhong ◽  
Yi Yu ◽  
Zhaojiang Shi
Keyword(s):  
Transition Metal ◽  
Organic Synthesis ◽  
Transition Metal Catalysis ◽  
Metal Catalysis

The merger of transition-metal catalysis and electrochemistry has been emerging as a very versatile and robust synthetic tool in organic synthesis. Like in their non-electrochemical variants, ligands also play crucial...

Insertion Reaction of 2-Halo-N-allylanilines with K2S Involving Trisulfur Radical Anion: Synthesis of Benzothiazole Derivatives under Transition-Metal-Free Conditions

Synthesis ◽  
2020 ◽  
Author(s):  
Yan-Wei Zhao ◽  
Shun-Yi Wang ◽  
Xin-Yu Liu ◽  
Tian Jiang ◽  
Weidong Rao
Keyword(s):  
Transition Metal ◽  
Radical Anion ◽  
Radical Cyclization ◽  
Transition Metal Catalysis ◽  
Insertion Reaction ◽  
Metal Catalysis ◽  
Metal Free ◽  
Benzothiazole Derivatives

AbstractA synthesis of benzothiazole derivatives through the reaction of 2-halo-N-allylanilines with K2S in DMF is developed. The trisulfur radical anion S3·–, which is generated in situ from K2S in DMF, initiates the reaction without transition-metal catalysis or other additives. In addition, two C–S bonds are formed and heteroaromatization of benzothiazole is triggered by radical cyclization and H-shift.

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