scholarly journals Functional-Group-Tolerant, Silver-Catalyzed N–N Bond Formation by Nitrene Transfer to Amines

2017 ◽  
Vol 139 (6) ◽  
pp. 2216-2223 ◽  
Author(s):  
Lourdes Maestre ◽  
Ruth Dorel ◽  
Óscar Pablo ◽  
Imma Escofet ◽  
W. M. C. Sameera ◽  
...  
Keyword(s):  
Functional Group ◽  
Bond Formation ◽  
Nitrene Transfer

Modern Organic Synthesis in the Laboratory

2008 ◽  
Author(s):  
Jie Jack Li ◽  
Chris Limberakis ◽  
Derek A. Pflum
Keyword(s):  
Organic Chemistry ◽  
Graduate Students ◽  
Organic Synthesis ◽  
Functional Group ◽  
Bond Formation ◽  
Reaction Conditions ◽  
Carbon Bond ◽  
Oxidation Reduction ◽  
Carbon Carbon Bond ◽  
Daunting Task

Searching for reaction in organic synthesis has been made much easier in the current age of computer databases. However, the dilemma now is which procedure one selects among the ocean of choices. Especially for novices in the laboratory, it becomes a daunting task to decide what reaction conditions to experiment with first in order to have the best chance of success. This collection intends to serve as an "older and wiser lab-mate" one could have by compiling many of the most commonly used experimental procedures in organic synthesis. With chapters that cover such topics as functional group manipulations, oxidation, reduction, and carbon-carbon bond formation, Modern Organic Synthesis in the Laboratory will be useful for both graduate students and professors in organic chemistry and medicinal chemists in the pharmaceutical and agrochemical industries.

scholarly journals A general method for site-selective Csp3–S bond formation via cooperative catalysis

2020 ◽  
Vol 11 (5) ◽  
pp. 1276-1282 ◽  
Author(s):  
Yuman Qin ◽  
Yujie Han ◽  
Yongzhen Tang ◽  
Junfa Wei ◽  
Mingyu Yang
Keyword(s):  
Functional Group ◽  
Bond Formation ◽  
Aliphatic Amines ◽  
Cooperative Catalysis ◽  
Site Selective ◽  
General Method

A copper-catalyzed site-selective thiolation of Csp3–H bonds of aliphatic amines was developed. The method features a broad substrate scope and good functional group tolerance.

Metal-catalyzed radical-type transformation of unactivated alkyl halides with C–C bond formation under photoinduced conditions

2019 ◽  
Vol 6 (13) ◽  
pp. 2183-2199 ◽  
Author(s):  
Shengqing Ye ◽  
Tianyi Xiang ◽  
Xiaofang Li ◽  
Jie Wu
Keyword(s):  
Functional Group ◽  
Bond Formation ◽  
Alkyl Halides ◽  
Type Transformation ◽  
Recent Advances ◽  
Metal Catalyzed ◽  
Radical Type

Recent advances in the metal-catalyzed radical-type transformation of unactivated alkyl halides with C–C bond formation under photoinduced conditions are summarized. Usually, a broad reaction scope is observed including tertiary, secondary, and primary alkyl halides, with good functional group compatibility.

scholarly journals Nickel-Catalyzed Thiolation of Aryl Nitriles

2021 ◽  
Author(s):  
Tristan Delcaillau ◽  
Bill Morandi
Keyword(s):  
Late Stage ◽  
Functional Group ◽  
Bond Activation ◽  
Bond Formation ◽  
Aryl Nitriles

<div>A nickel-catalyzed thiolation of aryl nitriles has been developed to access functionalized aryl thioethers. The ligand dcype (1,2 Bis(dicyclohexylphosphino)ethane) as well as the base KOtBu (potassium tert-butoxide) are essential to achieve this transformation. This scalable and practical process involves both a C–C bond activation and a C–S bond formation. Furthermore, this reaction shows a high functional-group tolerance and enables the late-stage functionalization of important molecules.</div>

scholarly journals Site-Selective Alkoxylation of Benzylic C–H Bonds via Photoredox Catalysis

2019 ◽  
Author(s):  
Byung Joo Lee ◽  
kimberly deglopper ◽  
Tehshik Yoon
Keyword(s):  
Late Stage ◽  
Functional Group ◽  
Bond Formation ◽  
Bioactive Molecules ◽  
Site Selectivity ◽  
Wide Range ◽  
High Site ◽  
Alkoxy Groups ◽  
Site Selective ◽  
Mediated Oxidation

<div> <div> <div> <p>There are relatively few methods that accom- plish the selective alkoxylation of sp3-hybridized C–H bonds, particularly in comparison to the numerous analogous strate- gies for C–N and C–C bond formation. We report a photo- catalytic protocol for the functionalization of benzylic C–H bonds with a wide range of readily available oxygen nucleo- philes. Our strategy merges the photoredox activation of arenes with copper(II)-mediated oxidation of the resulting benzylic radicals, which enables the introduction of benzylic C–O bonds with high site selectivity, chemoselectivity, and functional group tolerance. This method enables the late- stage introduction of complex alkoxy groups into bioactive molecules, providing a practical new tool with potential appli- cations in synthesis and medicinal chemistry. </p> </div> </div> </div>

Electronically Asynchronous Transition States for C-N Bond Formation by Electrophilic [Coᴵᴵᴵ(TAML)]-Nitrene Radical Complexes Involving Substrate-to-Ligand Single-Electron Transfer and a Cobalt-Centered Spin Shuttle

2019 ◽  
Author(s):  
Nicolaas P. van Leest ◽  
Martijn A. Tepaske ◽  
Jarl Ivar van der Vlugt ◽  
Bas de Bruin
Keyword(s):  
Electron Transfer ◽  
Bond Formation ◽  
Macrocyclic Ligand ◽  
Transition States ◽  
Lone Pair ◽  
Single Electron ◽  
Nucleophilic Attack ◽  
Single Electron Transfer ◽  
Radical Species ◽  
Nitrene Transfer

The oxidation state of the redox non-innocent TAML (Tetra-Amido Macrocyclic Ligand) scaffold was recently shown to affect the formation of nitrene radical species on cobalt(III) upon reaction with PhI=NNs [J. Am. Chem. Soc. 2020, DOI: 10.1021/jacs.9b11715]. For the neutral [Co<sup>III</sup>(TAMLsq)] complex this leads to the doublet (S = ½) mono-nitrene radical species [Co<sup>III</sup>(TAMLq)(N<sup>•</sup>Ns)], while a triplet (S = 1) bis-nitrene radical species [Co<sup>III</sup>(TAML<sup>q</sup>)(N<sup>•</sup>Ns)<sub>2</sub>]<sup>‒</sup> is generated from the anionic [Co<sup>III</sup>(TAML<sup>red</sup>)]<sup>‒</sup> complex. The one-electron reduced Fischer-type nitrene radicals (N<sup>•</sup>Ns<sup>‒</sup>) are formed through single (mono-nitrene) or double (bis-nitrene) ligand-to-substrate single-electron transfer (SET). In this work we describe the reactivity and mechanisms of these nitrene radical complexes in catalytic aziridination. We report that [Co<sup>III</sup>(TAML<sup>sq</sup>)] and [Co<sup>III</sup>(TAML<sup>red</sup>)]<sup>‒</sup> are both effective catalysts for chemoselective (C=C versus C‒H bonds) and diastereoselective aziridination of styrene derivatives, cyclohexene and 1-hexene under mild and even aerobic (for [Co<sup>III</sup>(TAML<sup>red</sup>)]<sup>‒</sup>) conditions. Experimental (Hammett plots, radical inhibition, catalyst decomposition tests) and computational (DFT, CASSCF) studies reveal that [Co<sup>III</sup>(TAML<sup>q</sup>)(N<sup>•</sup>Ns)], [Co<sup>III</sup>(TAML<sup>q</sup>)(N<sup>•</sup>Ns)<sub>2</sub>]<sup>‒</sup> and [Co<sup>III</sup>(TAML<sup>sq</sup>)(N<sup>•</sup>Ns)]<sup>–</sup> are key electrophilic intermediates in the aziridination reactions. Surprisingly, the electrophilic one-electron reduced Fischer-type nitrene radicals do not react as would be expected for nitrene radicals (i.e. via radical addition and radical rebound). Instead, nitrene transfer proceeds through unusual electronically asynchronous transition states, in which (partial) styrene substrate to TAML ligand (single) electron transfer precedes C-N coupling. The actual C-N bond formation processes are best described as involving a nucleophilic attack of the nitrene (radical) lone pair at the thus (partially) formed styrene radical cation. These processes are coupled to TAML-to-cobalt and cobalt-to-nitrene single-electron transfer, effectively leading to formation of an amido-[gamma]-benzyl radical (Ns–N–CH<sub>2</sub>–<sup>•</sup>CH–Ph) bound to an intermediate spin (S = 1) cobalt(III) center. Hence, the TAML moiety can be regarded to act as a transient electron acceptor, the cobalt center behaves as a spin shuttle and the nitrene radical acts as a nucleophile. Such a mechanism for (cobalt catalyzed) nitrene transfer was hitherto unknown and complements the known concerted and stepwise mechanisms for N-group transfer.

A Review of Ruthenium-catalyzed C-N Bond Formation Reactions for the Synthesis of Five-membered N-heterocycles

2019 ◽  
Vol 23 (18) ◽  
pp. 1901-1944 ◽  
Author(s):  
Navjeet Kaur ◽  
Neha Ahlawat ◽  
Yamini Verma ◽  
Pooja Grewal ◽  
Pranshu Bhardwaj
Keyword(s):  
Heterocyclic Compounds ◽  
Functional Group ◽  
Bond Formation ◽  
Review Article ◽  
Transition Metal Catalysts ◽  
Heterocyclic Chemistry ◽  
Research Groups ◽  
Reaction Conditions ◽  
Alternative Pathways ◽  
Molecular Complexity

The field of heterocyclic chemistry has been revolutionized using transition metal catalysts in recent years. Various research groups have focused on the development of general protocols to achieve better functional group compatibilities and greater levels of molecular complexity under mild reaction conditions, using easily available starting substrates. The methodologies used earlier for their synthesis were less approachable to organic chemists because of their high cost, highly specified instrumentation and inconvenient methods. For both stereoselective and regioselective synthesis of five-membered nitrogen- containing heterocycles, cyclic reactions that are Ru-catalyzed have known to be very efficient. These methods have many advantages as compared to alternative pathways involved in the synthesis of heterocyclic compounds. In this review article, we concentrated on the synthesis of nitrogen-containing five-membered heterocycles in the presence of a ruthenium catalyst. This review mostly covers the literature published during the period from 1977-2019.

Ligand- and catalyst-free intramolecular C-S bond formation: direct access to indalothiochromen- 4-ones

2015 ◽  
Vol 21 (3) ◽  
pp. 159-163 ◽  
Author(s):  
T.A. Jenifer Vijay ◽  
Nagarakere C. Sandhya ◽  
C.S. Pavankumar ◽  
Kanchugarakoppal S. Rangappa ◽  
Kempegowda Mantelingu
Keyword(s):  
Functional Group ◽  
Direct Synthesis ◽  
Bond Formation ◽  
Direct Access ◽  
Mild Conditions ◽  
Catalyst Free

AbstractAn efficient ligand- and catalyst-free intramolecular S-arylation leading to the direct synthesis of indalothiochromen-4-ones from simple dithioesters under mild conditions has been developed. This method is particularly noteworthy given its experimental simplicity, high generality, and good functional group toleration.

An Efficient Copper-Catalyzed C(sp2)–S Formation Starting from Aryl Iodides and Tetramethylthiuram Monosulfide (TMTM)

Synthesis ◽  
2020 ◽  
Author(s):  
Zhi-Bing Dong ◽  
Yue-Xiao Wu ◽  
Kang Peng ◽  
Jing-Hang Li
Keyword(s):  
Active Sites ◽  
Functional Group ◽  
Bond Formation ◽  
Cost Effective ◽  
Aryl Iodides ◽  
High Yields

A new, efficient copper-catalyzed C(sp2)–S formation of phenyl dithiocarbamates starting from aryl iodides and tetramethylthiuram monosulfide (TMTM) was developed. The target compounds, phenyl dithiocarbamates with active sites, were synthesized smoothly in good to excellent yields. The easy performance, high yields, decent functional group compatibility, and cost-effective substrates make the protocol practical and attractive in C–S bond formation.

Sign in / Sign up

Export Citation Format

Share Document