Reductive Hydrobenzylation of Terminal Alkynes via Photoredox and Nickel Dual Catalysis

2021 ◽  
Author(s):  
Xian Zhao ◽  
Shengqing Zhu ◽  
Feng-Ling Qing ◽  
Lingling Chu
Keyword(s):  
Terminal Alkynes ◽  
Alkyl Amines ◽  
Benzyl Chlorides ◽  
Migratory Insertion ◽  
Dual Catalysis

A photoredox/nickel dual catalyzed reductive hydrobenzylation of alkynes and benzyl chlorides by employing alkyl amines as a stoichiometric reductant is described. This synergistic protocol proceeds via Markovnikov-selective migratory insertion of...

scholarly journals Selective Manganese-Catalyzed Dimerization and Cross-Coupling of Terminal Alkynes

2021 ◽  
Author(s):  
Stefan Weber ◽  
Luis F. Veiros ◽  
Karl Kirchner
Keyword(s):  
Dft Calculations ◽  
Precious Metal ◽  
Bond Cleavage ◽  
Cross Coupling ◽  
Metal Catalyst ◽  
Catalyst Loading ◽  
Terminal Alkynes ◽  
Migratory Insertion ◽  
Earth Abundant ◽  
First Time

<div>For the first time, an efficient manganese-catalyzed dimerization of terminal alkynes to afford 1,3-enynes is described. This reaction is atom economic, implementing an inexpensive, earth abundant non-precious metal catalyst. The pre-catalyst is the bench-stable alkyl bisphosphine Mn(I) complex fac-[Mn(dippe)(CO)3(CH2CH2CH3)]. The catalytic process is initiated by migratory insertion of a CO ligand into the Mn-alkyl bond to yield an acyl intermediate which undergoes rapid C-H bond cleavage of the alkyne forming an active Mn(I) acetylide catalyst [Mn(dippe)(CO)2(C≡CPh)(η2-HC≡CPh)] together with liberated butanal. A range of aromatic and aliphatic terminal alkynes were efficiently and selectively converted into head-to-head Z-1,3-enynes and head-to-tail gem-1,3-enynes, respectively, in good to excellent yields. Moreover, cross-coupling of aromatic and aliphatic alkynes yields selectively head-to-tail gem-1,3-enynes. In all cases, the reactions were performed at 70 °C with a catalyst loading of 1-2 mol %. A mechanism based on DFT calculations is presented.</div><div><br></div>

scholarly journals Selective Manganese-Catalyzed Dimerization and Cross-Coupling of Terminal Alkynes

2021 ◽  
Author(s):  
Stefan Weber ◽  
Luis F. Veiros ◽  
Karl Kirchner
Keyword(s):  
Dft Calculations ◽  
Precious Metal ◽  
Bond Cleavage ◽  
Cross Coupling ◽  
Metal Catalyst ◽  
Catalyst Loading ◽  
Terminal Alkynes ◽  
Migratory Insertion ◽  
Earth Abundant ◽  
First Time

<div>For the first time, an efficient manganese-catalyzed dimerization of terminal alkynes to afford 1,3-enynes is described. This reaction is atom economic, implementing an inexpensive, earth abundant non-precious metal catalyst. The pre-catalyst is the bench-stable alkyl bisphosphine Mn(I) complex fac-[Mn(dippe)(CO)3(CH2CH2CH3)]. The catalytic process is initiated by migratory insertion of a CO ligand into the Mn-alkyl bond to yield an acyl intermediate which undergoes rapid C-H bond cleavage of the alkyne forming an active Mn(I) acetylide catalyst [Mn(dippe)(CO)2(C≡CPh)(η2-HC≡CPh)] together with liberated butanal. A range of aromatic and aliphatic terminal alkynes were efficiently and selectively converted into head-to-head Z-1,3-enynes and head-to-tail gem-1,3-enynes, respectively, in good to excellent yields. Moreover, cross-coupling of aromatic and aliphatic alkynes yields selectively head-to-tail gem-1,3-enynes. In all cases, the reactions were performed at 70 °C with a catalyst loading of 1-2 mol %. A mechanism based on DFT calculations is presented.</div><div><br></div>

Pd-catalyzed cross-coupling of terminal alkynes with ene-yne-ketones: access to conjugated enynes via metal carbene migratory insertion

2015 ◽  
Vol 51 (56) ◽  
pp. 11233-11235 ◽  
Author(s):  
Ying Xia ◽  
Zhen Liu ◽  
Rui Ge ◽  
Qing Xiao ◽  
Yan Zhang ◽  
...  
Keyword(s):  
Bond Formation ◽  
Cross Coupling ◽  
Terminal Alkynes ◽  
Conjugated Enynes ◽  
Migratory Insertion ◽  
Insertion Process

Pd-catalyzed oxidative cross-coupling of terminal alkynes with ene-yne-ketones has been developed, in which the ene-yne-ketones are served as carbene precursors and metal carbene migratory insertion process is the key step for C–C bond formation.

scholarly journals Nickel-Catalyzed Deaminative Sonogashira Coupling of Alkylpyridinium Salts Enabled by a New NN2 Pincer Ligand

2020 ◽  
Author(s):  
Xingjie Zhang ◽  
Di Qi ◽  
Chenchen Jiao ◽  
Xiaopan Liu ◽  
Guisheng Zhang
Keyword(s):  
High Efficiency ◽  
Materials Science ◽  
Alkylating Agents ◽  
Sonogashira Coupling ◽  
Terminal Alkynes ◽  
Pincer Ligand ◽  
One Pot ◽  
Alkyl Amines ◽  
Sonogashira Reactions ◽  
First Time

Abstract Alkynes are amongst the most valuable functional groups in organic chemistry and widely used in chemical biology, pharmacy, and materials science. However, the preparation of alkyl-substituted alkynes still remains elusive. Herein, a novel transformation is disclosed that enables the coupling of terminal alkynes with alkylpyridinium salts under Ni-catalysis. Key to the success of this coupling was the development of a new and readily accessible amide-type pincer ligand. This ligand allows naturally abundant alkyl amines as alkylating agents in Sonogashira reactions for the first time, and leads to diverse alkynes in excellent yields under mild conditions. Salient merits of this chemistry include broad substrates scope and functional group tolerance, gram-scale synthesis, one-pot transformation, versatile late-stage derivatizations as well as the use of inexpensive pre-catalyst and readily available substrates. The high efficiency and strong practicability bode well for the widespread applications of this strategy in constructing functional molecules, materials, and fine chemicals.

Concise Synthesis of GB22 by Endo-Selective Siloxycyclopropane Arylation

2019 ◽  
Author(s):  
Hannah E. Burdge ◽  
Takuya Oguma ◽  
Takahiro Kawajiri ◽  
Ryan Shenvi
Keyword(s):  
Intramolecular Cyclization ◽  
Cross Coupling ◽  
Building Blocks ◽  
Ring Expansion ◽  
Dual Catalysis ◽  
Acid Labile

<div><div><div><p>The first synthesis of GB22 was accomplished by a con- cise, modular route. Two building blocks converged in a novel sp3-sp2 attached-ring coupling that used Ir/Ni dual-catalysis to reverse the regioselectivity of siloxycy- clopropane arylation. This cross-coupling proved general to access β-substituted tetralones via ring-expansion of indanone-derived siloxycyclopropanes. The congested, bridging rings of the GB alkaloids were completed using an aluminum-HFIP complex that effected intramolecular cyclization of an acid-labile substrate.</p></div></div></div>

Concise Synthesis of GB22 by Endo-Selective Siloxycyclopropane Arylation

2019 ◽  
Author(s):  
Hannah E. Burdge ◽  
Takuya Oguma ◽  
Takahiro Kawajiri ◽  
Ryan Shenvi
Keyword(s):  
Intramolecular Cyclization ◽  
Cross Coupling ◽  
Building Blocks ◽  
Ring Expansion ◽  
Dual Catalysis ◽  
Acid Labile

<div><div><div><p>The first synthesis of GB22 was accomplished by a con- cise, modular route. Two building blocks converged in a novel sp3-sp2 attached-ring coupling that used Ir/Ni dual-catalysis to reverse the regioselectivity of siloxycy- clopropane arylation. This cross-coupling proved general to access β-substituted tetralones via ring-expansion of indanone-derived siloxycyclopropanes. The congested, bridging rings of the GB alkaloids were completed using an aluminum-HFIP complex that effected intramolecular cyclization of an acid-labile substrate.</p></div></div></div>

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