scholarly journals Dual-Catalytic Transition Metal Systems for Functionalization of Unreactive Sites of Molecules

2018 ◽  
Author(s):  
Dawid Lichosyt ◽  
Yang Zhang ◽  
Karolina Hurej ◽  
Pawel Dydio
Keyword(s):  
Transition Metal ◽  
Organic Synthesis ◽  
Functional Group ◽  
Aliphatic Alcohols ◽  
Catalytic Reactions ◽  
Allylic Alcohols ◽  
Catalytic Systems ◽  
Mild Conditions ◽  
Broad Scope ◽  
Activation Cycle

<b>Catalytic reactions occur readily at sites of starting materials that are both innately reactive and sterically accessible or that are predisposed by a functional group amenable to direct a catalyst. However, selective reactions at unbiased sites of substrates remain challenging and typically require additional pre-activation steps or the use of highly reactive reagents. Herein, we report dual-catalytic transition metal systems that merge a reversible activation cycle with a functionalization cycle, together enabling functionalization of substrates at their inherently unreactive sites. By engaging the Ru- or Fe-catalyzed equilibrium between an alcohol and an aldehyde, Pd-catalyzed <i>b</i>-arylation of aliphatic alcohols and Rh-catalyzed <i>g</i>-hydroarylation of allylic alcohols were developed. The mild conditions, functional group tolerance and broad scope of the methodologies (81 examples) demonstrate the synthetic applicability of the dual-catalytic systems. In a broader context, this work highlights the potential of the multi-catalytic approach to address challenging transformations to circumvent the multi-step procedures and the use of highly reactive reagents in organic synthesis.</b>

scholarly journals Dual-Catalytic Transition Metal Systems for Functionalization of Unreactive Sites of Molecules

2018 ◽  
Author(s):  
Dawid Lichosyt ◽  
Yang Zhang ◽  
Karolina Hurej ◽  
Pawel Dydio
Keyword(s):  
Transition Metal ◽  
Organic Synthesis ◽  
Functional Group ◽  
Aliphatic Alcohols ◽  
Catalytic Reactions ◽  
Allylic Alcohols ◽  
Catalytic Systems ◽  
Mild Conditions ◽  
Broad Scope ◽  
Activation Cycle

<b>Catalytic reactions occur readily at sites of starting materials that are both innately reactive and sterically accessible or that are predisposed by a functional group amenable to direct a catalyst. However, selective reactions at unbiased sites of substrates remain challenging and typically require additional pre-activation steps or the use of highly reactive reagents. Herein, we report dual-catalytic transition metal systems that merge a reversible activation cycle with a functionalization cycle, together enabling functionalization of substrates at their inherently unreactive sites. By engaging the Ru- or Fe-catalyzed equilibrium between an alcohol and an aldehyde, Pd-catalyzed <i>b</i>-arylation of aliphatic alcohols and Rh-catalyzed <i>g</i>-hydroarylation of allylic alcohols were developed. The mild conditions, functional group tolerance and broad scope of the methodologies (81 examples) demonstrate the synthetic applicability of the dual-catalytic systems. In a broader context, this work highlights the potential of the multi-catalytic approach to address challenging transformations to circumvent the multi-step procedures and the use of highly reactive reagents in organic synthesis.</b>

Direct and metal-free oxidative amination of sp3 C–H bonds for the construction of 2-hetarylquinazolin-4(3H)-ones

2016 ◽  
Vol 3 (9) ◽  
pp. 1096-1099 ◽  
Author(s):  
Huanhuan Liu ◽  
Tianran Zhai ◽  
Shiteng Ding ◽  
Yalei Hou ◽  
Xiangyu Zhang ◽  
...  
Keyword(s):  
Transition Metal ◽  
Functional Group ◽  
New Method ◽  
Oxidative Amination ◽  
Metal Free ◽  
Mild Conditions

New method for synthesis of 2-hetarylquinazolin-4(3H)-ones from 2-aminobenzamides and (2-azaaryl)methanes under transition-metal free conditions, featuring a wide substrate scope with a broad range of functional group tolerance under mild conditions.

scholarly journals Learning from B12 enzymes: biomimetic and bioinspired catalysts for eco-friendly organic synthesis

2018 ◽  
Vol 14 ◽  
pp. 2553-2567 ◽  
Author(s):  
Keishiro Tahara ◽  
Ling Pan ◽  
Toshikazu Ono ◽  
Yoshio Hisaeda
Keyword(s):  
Organic Synthesis ◽  
Reaction Mechanisms ◽  
Catalytic Reactions ◽  
Vitamin B ◽  
Catalytic Systems ◽  
New Approach ◽  
Enzyme Functions

Cobalamins (B12) play various important roles in vivo. Most B12-dependent enzymes are divided into three main subfamilies: adenosylcobalamin-dependent isomerases, methylcobalamin-dependent methyltransferases, and dehalogenases. Mimicking these B12 enzyme functions under non-enzymatic conditions offers good understanding of their elaborate reaction mechanisms. Furthermore, bio-inspiration offers a new approach to catalytic design for green and eco-friendly molecular transformations. As part of a study based on vitamin B12 derivatives including heptamethyl cobyrinate perchlorate, we describe biomimetic and bioinspired catalytic reactions with B12 enzyme functions. The reactions are classified according to the corresponding three B12 enzyme subfamilies, with a focus on our recent development on electrochemical and photochemical catalytic systems. Other important reactions are also described, with a focus on radical-involved reactions in terms of organic synthesis.

Bromotrifluoromethane: A Useful Reagent for Hydrotrifluoromethylation of Alkenes and Alkynes

Synlett ◽  
2018 ◽  
Vol 29 (08) ◽  
pp. 1028-1032 ◽  
Author(s):  
Xing Zheng ◽  
Xingang Zhang ◽  
Yu-Yan Ren
Keyword(s):  
Visible Light ◽  
Organic Synthesis ◽  
Functional Group ◽  
Mild Conditions ◽  
Industrial Material ◽  
Reaction Proceeds

Bromotrifluoromethane (CF3Br) is a simple, inexpensive and abundant industrial material employed as a trifluoromethylating reagent. However, only limited strategies using CF3Br as a fluorine source are reported. Herein, we describe a visible-light-induced hydrotrifluoromethylation of alkenes and alkynes with CF3Br. The reaction proceeds under mild conditions with good functional group tolerance, providing a new route for the application of BrCF3 in organic synthesis.

scholarly journals Olefin metathesis in air

2015 ◽  
Vol 11 ◽  
pp. 2038-2056 ◽  
Author(s):  
Lorenzo Piola ◽  
Fady Nahra ◽  
Steven P Nolan
Keyword(s):  
Transition Metal ◽  
Olefin Metathesis ◽  
Functional Group ◽  
High Oxidation State ◽  
Catalytic Systems ◽  
Metal Centers ◽  
Early Transition Metal ◽  
Significant Interest ◽  
High Oxidation ◽  
Metathesis Catalysts

Since the discovery and now widespread use of olefin metathesis, the evolution of metathesis catalysts towards air stability has become an area of significant interest. In this fascinating area of study, beginning with early systems making use of high oxidation state early transition metal centers that required strict exclusion of water and air, advances have been made to render catalysts more stable and yet more functional group tolerant. This review summarizes the major developments concerning catalytic systems directed towards water and air tolerance.

scholarly journals Iodonium-Catalyzed Carbonyl–Olefin Metathesis Reactions

Synlett ◽  
2019 ◽  
Vol 30 (17) ◽  
pp. 1966-1970 ◽  
Author(s):  
Giulia Oss ◽  
Thanh Vinh Nguyen
Keyword(s):  
Transition Metal ◽  
Organic Compounds ◽  
Organic Synthesis ◽  
Olefin Metathesis ◽  
Lewis Acids ◽  
Functional Group ◽  
Iodine Monochloride ◽  
Metathesis Reaction ◽  
Reaction Conditions ◽  
Recent Developments

The carbonyl–olefin metathesis reaction has become increasingly important in organic synthesis due to its versatility in functional group interconversion chemistry. Recent developments in the field have identified a number of transition-metal and organic Lewis acids as effective catalysts for this reaction. Herein, we report the use of simple organic compounds such as N-iodosuccinimide or iodine monochloride to catalyze the carbonyl–olefin metathesis process under mild reaction conditions. This work broadens the scope of this chemical transformation to include iodonium sources as simple and practical catalysts.

Iron(III)/TEMPO-Catalyzed Synthesis of 2,5-Disubstituted 1,3,4-Oxadiazoles by Oxidative Cyclization under Mild Conditions

Synlett ◽  
2017 ◽  
Vol 28 (11) ◽  
pp. 1373-1377 ◽  
Author(s):  
Chengrong Ding ◽  
Guofu Zhang ◽  
Yidong Yu ◽  
Yiyong Zhao ◽  
Xiaoqiang Xie
Keyword(s):  
Functional Group ◽  
Oxidative Cyclization ◽  
Mild Conditions ◽  
Broad Scope ◽  
Oxadiazole Derivatives ◽  
High Yields

A simple and efficient cationic Fe(III)/TEMPO-catalyzed oxidative cyclization of aroyl hydrazones has been developed for the synthesis of 2,5-disubstituted 1,3,4-oxadiazole derivatives. The reaction offers a broad scope, good functional-group tolerance, and high yields under mild conditions in the presence of O2.

scholarly journals One-Pot Reductive Acetylation of Aldehydes using 1-Hydrosilatrane in Acetic Acid

SynOpen ◽  
2019 ◽  
Vol 03 (01) ◽  
pp. 1-3 ◽  
Author(s):  
Reuben James ◽  
Sharon Herlugson ◽  
Sami Varjosaari ◽  
Vladislav Skrypai ◽  
Zainab Shakeel ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Organic Synthesis ◽  
Functional Group ◽  
Building Blocks ◽  
Flash Chromatography ◽  
Primary Alcohols ◽  
Facile Synthesis ◽  
One Pot ◽  
Aryl Aldehydes ◽  
Mild Conditions

A one-pot, direct reductive acetylation of aldehydes was achieved under mild conditions using 1-hydrosilatrane as a safe and easily accessible catalyst. Described herein is a facile synthesis that produces acylated primary alcohols that can serve as valuable building blocks for organic synthesis. The method has good functional group tolerance and works for a range of aryl aldehydes, with the notable exception of electron-rich arenes. A library of esters was isolated by flash chromatography in yields as high as 92%.

scholarly journals Palladium-Catalyzed Cross-Coupling of Gem-Bromofluoroalkenes with Alkylboronic Acids for the Synthesis of Alkylated Monofluoroalkenes

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5532
Author(s):  
Laëtitia Chausset-Boissarie ◽  
Nicolas Cheval ◽  
Christian Rolando
Keyword(s):  
Organic Synthesis ◽  
Functional Group ◽  
Materials Science ◽  
Cross Coupling ◽  
High Yield ◽  
Efficient Synthesis ◽  
Mild Conditions ◽  
Wide Range ◽  
Palladium Catalyzed ◽  
Novel Strategy

Monofluoroalkenes are versatile fluorinated synthons in organic synthesis, medicinal chemistry and materials science. In light of the importance of alkyl-substituted monofluoroalkenes efficient synthesis of these moieties still represents a synthetic challenge. Herein, we described a mild and efficient methodology to obtain monofluoroalkenes through a stereospecific palladium-catalyzed alkylation of gem-bromofluoroalkenes with primary and strained secondary alkylboronic acids under mild conditions. This novel strategy gives access to a wide range of functionalized tri- and tetrasubstituted monofluoroalkenes in high yield, with good functional group tolerance, independently from the gem-bromofluoroalkenes geometry.

scholarly journals Transition Metal Free Sandmeyer-Type Reductive Disulfuration of Anilines

2021 ◽  
Author(s):  
Shiqi Chen ◽  
Si Cao ◽  
Chaoyang Liu ◽  
Baoxu Wang ◽  
Xiaorui Ren ◽  
...  
Keyword(s):  
Transition Metal ◽  
Sandmeyer Reaction ◽  
Metal Free ◽  
Mild Conditions ◽  
Broad Scope ◽  
Ligand Free ◽  
Metal Ligand

A transition metal/ligand free disulfuration of anilines with disulfur transfer reagents (dithiosulfonate or tetrasulfide) is reported herein. The reaction, which can be considered as a reductive disulfuration variation of the classic Sandmeyer reaction, is performed under mild conditions and exhibits broad scope across aniline substrate and disulfur transfer reagent classes. The gram-scale synthesis of disulfides is successfully achieved through this method, rendering the approach highly valuable. <br>

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