Metal-free reductive coupling of aliphatic aldehydes/ketones with 4-cyanopyridines: expanded scope and mechanistic studies

2020 ◽  
Vol 7 (18) ◽  
pp. 2744-2751
Author(s):  
Liuzhou Gao ◽  
Guoqiang Wang ◽  
Hui Chen ◽  
Jia Cao ◽  
Xiaoshi Su ◽  
...  
Keyword(s):  
Reductive Coupling ◽  
Mechanistic Studies ◽  
Aliphatic Aldehydes ◽  
Metal Free ◽  
Wide Range ◽  
Convenient Route

A practical B2pin2 mediated reductive coupling of 4-cyanopyridine with aliphatic aldehydes/ketones has been established. This metal-free protocol provides a convenient route to construct a wide range of C4-pyridine-functionalized alcohols.

Deuterated Aryl Alkyl Ethers Synthesis via Nucleophilic Etherification of Aryl Alkyl Ethers and Thioethers with Deuterated Alcohols

Synlett ◽  
2019 ◽  
Vol 30 (15) ◽  
pp. 1805-1809
Author(s):  
Shuai Li ◽  
Xia Wang ◽  
Xin-Ge Yang ◽  
Gui-Quan Yu ◽  
Xue-Qiang Wang
Keyword(s):  
Transition Metal ◽  
Nucleophilic Aromatic Substitution ◽  
Aromatic Substitution ◽  
Mechanistic Studies ◽  
Reaction Conditions ◽  
Metal Free ◽  
Wide Range ◽  
Alkyl Ethers

A transition-metal-free etherification protocol that is capable of synthesizing deuterated ethers is described. A wide range of aryl alkyl ethers and thioethers were suitable for this transformation owing to the mild reaction conditions. Besides, a series of sterically bulky deuterated alcohols were successfully incorporated into cyano-substituted arenes. The results of mechanistic studies suggested this reaction might take place via nucleophilic aromatic substitution pathway.

scholarly journals Nickel-Catalyzed Reductive Coupling of Unactivated Alkyl Bromides and Aliphatic Aldehydes

2021 ◽  
Author(s):  
Cole Cruz ◽  
John Montgomery
Keyword(s):  
Functional Groups ◽  
Catalytic System ◽  
Cross Coupling ◽  
Secondary Alcohols ◽  
Reductive Coupling ◽  
Aliphatic Aldehydes ◽  
Alkyl Bromide ◽  
Alkyl Bromides ◽  
Wide Range ◽  
Ni Species

We report the development of a mild, convenient coupling of aliphatic aldehydes and unactivated alkyl bromides. The catalytic system features the use of a common Ni(II) precatalyst and a readily available bisoxazoline ligand and affords silyl-protected secondary alcohols. The reaction is operationally simple, utilizing Mn as a stoichiometric reductant, and tolerates a wide range of functional groups. Initial mechanistic experiments support a mechanism featuring an alpha-silyloxy Ni species which undergoes formal oxidative addition of the alkyl bromide species via a reductive cross-coupling pathway.

scholarly journals Nickel-Catalyzed Reductive Coupling of Unactivated Alkyl Bromides and Aliphatic Aldehydes

2021 ◽  
Author(s):  
Cole Cruz ◽  
John Montgomery
Keyword(s):  
Functional Groups ◽  
Catalytic System ◽  
Cross Coupling ◽  
Secondary Alcohols ◽  
Reductive Coupling ◽  
Aliphatic Aldehydes ◽  
Alkyl Bromide ◽  
Alkyl Bromides ◽  
Wide Range ◽  
Ni Species

We report the development of a mild, convenient coupling of aliphatic aldehydes and unactivated alkyl bromides. The catalytic system features the use of a common Ni(II) precatalyst and a readily available bisoxazoline ligand and affords silyl-protected secondary alcohols. The reaction is operationally simple, utilizing Mn as a stoichiometric reductant, and tolerates a wide range of functional groups. Initial mechanistic experiments support a mechanism featuring an alpha-silyloxy Ni species which undergoes formal oxidative addition of the alkyl bromide species via a reductive cross-coupling pathway.

scholarly journals Nickel-Catalyzed Decarboxylative Coupling of Redox-Active Esters with Aliphatic Aldehydes

2021 ◽  
Author(s):  
Jichao Xiao ◽  
Zhenning Li ◽  
John Montgomery
Keyword(s):  
Catalytic Reactions ◽  
Reductive Coupling ◽  
Nickel Catalysis ◽  
Mechanistic Studies ◽  
Radical Chain ◽  
Aliphatic Aldehydes ◽  
Active Esters ◽  
Redox Active ◽  
Decarboxylative Coupling ◽  
Nucleophilic Reagents

The addition of alkyl fragments to aliphatic aldehydes is a highly desirable transformation for fragment couplings, yet existing methods come with operational challenges related to the basicity and instability of the nucleophilic reagents commonly employed. We report herein that nickel catalysis using a readily available bioxazoline (BiOx) ligand can catalyze the reductive coupling of redox-active esters with aliphatic aldehydes using zinc metal as the reducing agent to deliver silyl-protected secondary alcohols. This protocol is operationally simple, proceeds under mild conditions, and tolerates a variety of functional groups. Initial mechanistic studies suggest a radical chain pathway. Additionally, alkyl tosylates and epoxides are suitable alkyl precursors to this transformation providing a versatile suite of catalytic reactions for the functionalization of aliphatic aldehydes.

Dual Roles of Rongalite: Reductive Coupling Reaction to Construct Thiosulfonates Using Sulfonyl Hydrazides

Synlett ◽  
2020 ◽  
Vol 32 (01) ◽  
pp. 81-85
Author(s):  
Chengrong Ding ◽  
Guofu Zhang ◽  
Qiankun Fan ◽  
Yiyong Zhao ◽  
Huimin Wang
Keyword(s):  
Transition Metal ◽  
Coupling Reaction ◽  
Reductive Coupling ◽  
Mechanistic Studies ◽  
Dual Roles ◽  
Metal Free ◽  
Operational Simplicity

AbstractA tunable and practical transformation of structurally diverse sulfonyl hydrazides into thiosulfonates in the presence of Rongalite (NaHSO2·CH2O) was developed. Transition-metal-free conditions, operational simplicity, and readily available reagents are the striking features of this protocol. It is the first example for the synthesis of thiosulfonates using sulfonyl hydrazides with the assistance of reductant. Additionally, the mechanistic studies revealed that this transformation probably undergoes via a reducing–coupling pathway.

Synthesis of Acetamides from Aryl Amines and Acetonitrile by Diazotization under Metal-Free Conditions

Synlett ◽  
2019 ◽  
Vol 30 (19) ◽  
pp. 2169-2172 ◽  
Author(s):  
Yao-Fu Zeng ◽  
Yi-Na Li ◽  
Na-Na Zhang ◽  
Huan Kang ◽  
Pan Duan ◽  
...  
Keyword(s):  
Functional Groups ◽  
Coupling Reaction ◽  
Mechanistic Studies ◽  
Metal Free ◽  
Wide Range ◽  
Aryl Amines

An efficient and metal-free coupling reaction has been developed that affords acetamides from the corresponding aryl amines and acetonitrile. This method tolerates a wide range of functional groups and is selective toward aryl amines. Preliminary mechanistic studies were conducted.

Synthetic and Mechanistic Studies of a Versatile Heteroaryl Thioether Directing Group for Pd(II) Catalysis

2019 ◽  
Author(s):  
Andrew Romine ◽  
Kin Yang ◽  
Malkanthi Karunananda ◽  
Jason Chen ◽  
Keary Engle
Keyword(s):  
Mechanistic Studies ◽  
Salvianolic Acid ◽  
Wide Range ◽  
Computational Data ◽  
Synthetic Utility ◽  
Directing Group ◽  
High Yields ◽  
Julia Olefination ◽  
Reaction Progress Kinetic Analysis

A weakly coordinating monodentate heteroaryl thioether directing group has been developed for use in Pd(II) catalysis to orchestrate key elementary steps in the catalytic cycle that require conformational flexibility in a manner that is difficult to accomplish with traditional strongly coordinating directing groups. This benzothiazole thioether, (BT)S, directing group can be used to promote oxidative Heck reactivity of internal alkenes providing a wide range of products in moderate to high yields. To demonstrate the broad applicability of this directing group, arene C–H olefination was also successfully developed. Reaction progress kinetic analysis provides insights into the role of the directing group in each reaction, which is supplemented with computational data for the oxidative Heck reaction. Furthermore, this (BT)S directing group can be transformed into a number of synthetically useful functional groups, including a sulfone for Julia olefination, allowing it to serve as a “masked olefin” directing group in synthetic planning. In order to demonstrate this synthetic utility, natural products (+)-salvianolic acid A and salvianolic acid F are formally synthesized using the (BT)S directed C–H olefination as the key step.

p-Sulfonic acid calix[n]arene catalyzed synthesis of bioactive heterocycles: A review

2020 ◽  
Vol 24 ◽  
Author(s):  
Bubun Banerjee ◽  
Gurpreet Kaur ◽  
Navdeep Kaur
Keyword(s):  
Supramolecular Chemistry ◽  
Sulfonic Acid ◽  
Catalytic Efficiency ◽  
The Other ◽  
Reaction Conditions ◽  
Metal Free ◽  
Bioactive Scaffolds ◽  
Wide Range ◽  
Efficient Alternative ◽  
Bioactive Heterocycles

: Metal-free organocatalysts are becoming an important tool for the sustainable developments of various bioactive heterocycles. On the other hand, during last two decades, calix[n]arenes have been gaining considerable attention due to their wide range of applicability in the field of supramolecular chemistry. Recently, sulfonic acid functionalized calix[n] arenes are being employed as an efficient alternative catalyst for the synthesis of various bioactive scaffolds. In this review we have summarized the catalytic efficiency of p-sulfonic acid calix[n]arenes for the synthesis of diverse biologically promising scaffolds under various reaction conditions. There is no such review available in the literature showing the catalytic applicability of p-sulfonic acid calix[n]arenes. Therefore, we strongly believe that this review will surely attract those researchers who are interested about this fascinating organocatalyst.

Metal-free Reductive Coupling of Biphenyl Tosylhydrazones with Phenols or Benzyl Alcohols

2017 ◽  
Vol 14 (10) ◽  
Author(s):  
Yang Liu ◽  
Ping Liu ◽  
Yan Liu ◽  
Yu Wei ◽  
Bin Dai
Keyword(s):  
Reductive Coupling ◽  
Benzyl Alcohols ◽  
Metal Free
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