Direct Cyclization of Alkenyl Thioester via Transition Metal‐hydrogen Atom Transfer/radical‐polar Crossover Mechanism

2019 ◽  
Author(s):  
Shiori Date ◽  
Kensei Hamasaki ◽  
Karen Sunagawa ◽  
Hiroki Koyama ◽  
Chikayoshi Sebe ◽  
...  
Keyword(s):  
Natural Products ◽  
Hydrogen Atom ◽  
Transition Metal ◽  
Hydrogen Atom Transfer ◽  
Synthetic Method ◽  
Atom Transfer ◽  
Reaction Conditions ◽  
Hydride Hydrogen ◽  
Sulfur Heterocycles ◽  
One Step

<div>We report here a catalytic, Markovnikov selective, and scalable synthetic method for the synthesis of saturated sulfur heterocycles, which are found in the structures of pharmaceuticals and natural products, in one step from an alkenyl thioester. Unlike a potentially labile alkenyl thiol, an alkenyl thioester is stable and easy to prepare. The powerful Co catalysis via a cobalt hydride hydrogen atom transfer and radical-polar crossover mechanism enabled simultaneous cyclization and deprotection. The substrate scope was expanded by the extensive optimization of the reaction conditions and tuning of the thioester unit.</div>

Direct Cyclization of Alkenyl Thioester via Transition Metal‐hydrogen Atom Transfer/radical‐polar Crossover Mechanism

2019 ◽  
Author(s):  
Shiori Date ◽  
Kensei Hamasaki ◽  
Karen Sunagawa ◽  
Hiroki Koyama ◽  
Chikayoshi Sebe ◽  
...  
Keyword(s):  
Natural Products ◽  
Hydrogen Atom ◽  
Transition Metal ◽  
Hydrogen Atom Transfer ◽  
Synthetic Method ◽  
Atom Transfer ◽  
Reaction Conditions ◽  
Hydride Hydrogen ◽  
Sulfur Heterocycles ◽  
One Step

<div>We report here a catalytic, Markovnikov selective, and scalable synthetic method for the synthesis of saturated sulfur heterocycles, which are found in the structures of pharmaceuticals and natural products, in one step from an alkenyl thioester. Unlike a potentially labile alkenyl thiol, an alkenyl thioester is stable and easy to prepare. The powerful Co catalysis via a cobalt hydride hydrogen atom transfer and radical-polar crossover mechanism enabled simultaneous cyclization and deprotection. The substrate scope was expanded by the extensive optimization of the reaction conditions and tuning of the thioester unit.</div>

Metal-hydride hydrogen atom transfer (MHAT) reactions in natural products synthesis

2021 ◽  
Author(s):  
Jinghua Wu ◽  
Zhiqiang Ma
Keyword(s):  
Natural Products ◽  
Hydrogen Atom ◽  
Metal Hydride ◽  
Transfer Reaction ◽  
Hydrogen Atom Transfer ◽  
Atom Transfer ◽  
Hydride Hydrogen ◽  
Natural Products Synthesis

Metal-hydride hydrogen atom transfer reaction (MHAT) plays an important role in the field of natural products synthesis. MHAT, as a powerful tool, has been employed by chemists to construct C-C,...

scholarly journals Catalytic Dealkylative Synthesis of Cyclic Carbamates and Ureas via Hydrogen Atom Transfer and Radical-Polar Crossover

2020 ◽  
Author(s):  
Takuya Nagai ◽  
Nao Mimata ◽  
Yoshihiro Terada ◽  
Chikayoshi Sebe ◽  
Hiroki Shigehisa
Keyword(s):  
Hydrogen Atom ◽  
Transition Metal ◽  
Bioactive Compounds ◽  
Functional Group ◽  
Hydrogen Atom Transfer ◽  
Membered Ring ◽  
Atom Transfer ◽  
Reaction Conditions ◽  
Reaction Proceeds ◽  
Scalable Synthesis

Guided by the transition metal hydrogen atom transfer and radical-polar crossover concept, we developed a catalytic, Markovnikov-selective, functional-group tolerant, and scalable synthesis of cyclic carbamates, which are found in the structures of many bioactive compounds. This method not only provides common oxazolidinones but also six-to-eight-membered ring products. The reaction proceeds through the intramolecular displacement of an alkylcobalt(IV) in-termediate and dealkylation by 2,4,6-collidine; the activation energies of these steps were calculated by DFT. Cyclic ureas and cyclic phosphoramidates were also synthesized under the same reaction conditions.

scholarly journals Catalytic Dealkylative Synthesis of Cyclic Carbamates and Ureas via Hydrogen Atom Transfer and Radical-Polar Crossover

2020 ◽  
Author(s):  
Takuya Nagai ◽  
Nao Mimata ◽  
Yoshihiro Terada ◽  
Chikayoshi Sebe ◽  
Hiroki Shigehisa
Keyword(s):  
Hydrogen Atom ◽  
Transition Metal ◽  
Bioactive Compounds ◽  
Functional Group ◽  
Hydrogen Atom Transfer ◽  
Membered Ring ◽  
Atom Transfer ◽  
Reaction Conditions ◽  
Reaction Proceeds ◽  
Scalable Synthesis

Guided by the transition metal hydrogen atom transfer and radical-polar crossover concept, we developed a catalytic, Markovnikov-selective, functional-group tolerant, and scalable synthesis of cyclic carbamates, which are found in the structures of many bioactive compounds. This method not only provides common oxazolidinones but also six-to-eight-membered ring products. The reaction proceeds through the intramolecular displacement of an alkylcobalt(IV) in-termediate and dealkylation by 2,4,6-collidine; the activation energies of these steps were calculated by DFT. Cyclic ureas and cyclic phosphoramidates were also synthesized under the same reaction conditions.

scholarly journals Trends in Ground-State Entropies for Transition Metal Based Hydrogen Atom Transfer Reactions

2009 ◽  
Vol 131 (12) ◽  
pp. 4335-4345 ◽  
Author(s):  
Elizabeth A. Mader ◽  
Virginia W. Manner ◽  
Todd F. Markle ◽  
Adam Wu ◽  
James A. Franz ◽  
...  
Keyword(s):  
Hydrogen Atom ◽  
Transition Metal ◽  
Ground State ◽  
Hydrogen Atom Transfer ◽  
Transfer Reactions ◽  
Atom Transfer ◽  
Atom Transfer Reactions

Transition-metal-free radical relay cyclization of vinyl azides with 1,4-dihydropyridines involving a 1,5-hydrogen-atom transfer: access to α-tetralone scaffolds

2020 ◽  
Vol 7 (22) ◽  
pp. 3638-3647
Author(s):  
Yangzhen Liao ◽  
Yu Ran ◽  
Guijun Liu ◽  
Peijun Liu ◽  
Xiaozu Liu
Keyword(s):  
Free Radical ◽  
Hydrogen Atom ◽  
Transition Metal ◽  
Hydrogen Atom Transfer ◽  
Atom Transfer ◽  
Metal Free ◽  
Vinyl Azides

The remote C(sp3)–H functionalization enabled by a radical-mediated 1,5-hydrogen-atom transfer (HAT) process using vinyl azides and 1,4-dihydropyridines as precursors has been described.

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