scholarly journals SOMOphilic Alkynylation of Unreactive Alkenes Enabled by Iron-Catalyzed Hydrogen Atom Transfer

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 33
Author(s):  
Binlin Zhao ◽  
Tianxiang Zhu ◽  
Mengtao Ma ◽  
Zhuangzhi Shi
Keyword(s):  
Hydrogen Atom ◽  
Hydrogen Atom Transfer ◽  
Catalytic Cycle ◽  
Atom Transfer ◽  
Iron Hydride ◽  
Internal Alkynes ◽  
Hydride Hydrogen ◽  
Transfer Protocol ◽  
Acetylenic Sulfones

We report an efficient and practical iron-catalyzed hydrogen atom transfer protocol for assembling acetylenic motifs into functional alkenes. Diversities of internal alkynes could be obtained from readily available alkenes and acetylenic sulfones with excellent Markovnikov selectivity. An iron hydride hydrogen atom transfer catalytic cycle was described to clarify the mechanism of this reaction.

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,...

Hydroalkylation of Olefins to form Quaternary Carbons

2019 ◽  
Author(s):  
Samantha Green ◽  
Tucker R. Huffman ◽  
Ruairí McCourt ◽  
Vincent van der Puyl ◽  
Ryan Shenvi
Keyword(s):  
Hydrogen Atom ◽  
Catalytic System ◽  
Metal Hydride ◽  
Hydrogen Atom Transfer ◽  
Alkyl Halides ◽  
Atom Transfer ◽  
Hydride Hydrogen ◽  
Radical Traps ◽  
Quaternary Carbons

Metal-hydride hydrogen atom transfer (MHAT) functionalizes unbiased alkenes with predictable branched (Markovnikov) selectivity. The breadth of these transformations has been confined to π-radical traps; no sp<sup>3 </sup>electrophiles have been reported. Here we describe a Mn/Ni dual catalytic system that allows for the hydroalkylation of unactivated olefins by unactivated alkyl halides, yielding aliphatic quaternary carbons.

Hydroalkylation of Olefins to form Quaternary Carbons

2019 ◽  
Author(s):  
Samantha Green ◽  
Tucker R. Huffman ◽  
Ruairí McCourt ◽  
Vincent van der Puyl ◽  
Ryan Shenvi
Keyword(s):  
Hydrogen Atom ◽  
Catalytic System ◽  
Metal Hydride ◽  
Hydrogen Atom Transfer ◽  
Alkyl Halides ◽  
Atom Transfer ◽  
Hydride Hydrogen ◽  
Radical Traps ◽  
Quaternary Carbons

Metal-hydride hydrogen atom transfer (MHAT) functionalizes unbiased alkenes with predictable branched (Markovnikov) selectivity. The breadth of these transformations has been confined to π-radical traps; no sp<sup>3 </sup>electrophiles have been reported. Here we describe a Mn/Ni dual catalytic system that allows for the hydroalkylation of unactivated olefins by unactivated alkyl halides, yielding aliphatic quaternary carbons.

Catalytic Synthesis of Cyclic Guanidines via Hydrogen Atom Transfer and Radical-Polar Crossover

2020 ◽  
Author(s):  
Shunya Ohuchi ◽  
Hiroki Koyama ◽  
Hiroki Shigehisa
Keyword(s):  
Hydrogen Atom ◽  
Functional Group ◽  
Hydrogen Atom Transfer ◽  
Catalytic Synthesis ◽  
Membered Ring ◽  
Biologically Active ◽  
Atom Transfer ◽  
Powerful Method ◽  
Protective Groups ◽  
The Common

A catalytic synthesis of cyclic guanidines, which are found in many biologically active compounds and natu-ral products, was developed, wherein transition-metal hydrogen atom transfer and radical-polar crossover were employed. This mild and functional-group tolerant process enabled the cyclization of alkenyl guanidines bearing common protective groups, such as Cbz and Boc. This powerful method not only provided the common 5- and 6-membered rings but also an unusual 7-membered ring. The derivatization of the products afforded various heterocycles. We also investigated the se-lective cyclization of mono-protected or hetero-protected (TFA and Boc) alkenyl guanidines and their further derivatiza-tions.

Sulfamides Direct Radical-Mediated Chlorination of Aliphatic C–H Bonds

2019 ◽  
Author(s):  
Melanie Short ◽  
Mina Shehata ◽  
Matthew Sanders ◽  
Jennifer Roizen
Keyword(s):  
Hydrogen Atom ◽  
Transfer Reaction ◽  
Hydrogen Atom Transfer ◽  
Chain Propagation ◽  
Propagation Mechanism ◽  
Atom Transfer ◽  
Radical Chain ◽  
Radical Intermediates ◽  
Transfer Processes ◽  
Unusual Position

Sulfamides guide intermolecular chlorine transfer to gamma-C(sp<sup>3</sup>) centers. This unusual position-selectivity arises because accessed sulfamidyl radical intermediates engage in otherwise rare 1,6-hydrogen-atom transfer processes. The disclosed chlorine-transfer reaction relies on a light-initiated radical chain-propagation mechanism to oxidize C(sp<sup>3</sup>)-H bonds.

Sulfamides Direct Radical-Mediated Chlorination of Aliphatic C–H Bonds

2019 ◽  
Author(s):  
Melanie Short ◽  
Mina Shehata ◽  
Matthew Sanders ◽  
Jennifer Roizen
Keyword(s):  
Hydrogen Atom ◽  
Transfer Reaction ◽  
Hydrogen Atom Transfer ◽  
Chain Propagation ◽  
Propagation Mechanism ◽  
Atom Transfer ◽  
Radical Chain ◽  
Radical Intermediates ◽  
Transfer Processes ◽  
Unusual Position

Sulfamides guide intermolecular chlorine transfer to gamma-C(sp<sup>3</sup>) centers. This unusual position-selectivity arises because accessed sulfamidyl radical intermediates engage in otherwise rare 1,6-hydrogen-atom transfer processes. The disclosed chlorine-transfer reaction relies on a light-initiated radical chain-propagation mechanism to oxidize C(sp<sup>3</sup>)-H bonds.

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