scholarly journals Unified Template Strategy for Editing Multiple Remote C–H Bonds

Author(s):  
Zhoulong Fan ◽  
Xiangyang Chen ◽  
Keita Tanaka ◽  
Han Seul Park ◽  
Nelson Y. S. Lam ◽  
...  

Through consecutive selective C–H functionalization at multiple sites, the direct molecular editing of heteroarene carbon-hydrogen (C–H) bonds has the potential to grant rapid access into diverse molecular space; a valuable but often challenging venture to achieve in medicinal chemistry. Contrasting with electronically-biased heterocyclic C–H bonds, remote benzocyclic C–H bonds on bicyclic aza-arenes are especially difficult to differentiate due to lack of intrinsic steric/electronic biases. Through careful consideration of distance and geometric parameters, we herein report a unified catalytic directing template strategy that enables the modular functionalization of chemically-similar and adjacent remote positions on bicyclic aza-arene scaffolds. Differentiated by using two structurally distinct catalytic directing templates, this method enables direct C–H olefination, alkynylation, and allylation at previously inaccessible C6 and C7 positions of quinolines, and is amenable to the iterative, modular, and late-stage C–H editing of quinoline-containing pharmacophores and pharmaceuticals. This report, in combination with our previous C5-selective template and other complementary methods, now fully establishes a unified ‘molecular editing’ strategy to directly modify aza-arene heterocycles at any given site.

2019 ◽  
Author(s):  
De-Wei Gao ◽  
Yang Gao ◽  
Huiling Shao ◽  
Tian-Zhang Qiao ◽  
Xin Wang ◽  
...  

Enantioenriched <i>α</i>-aminoboronic acids play a unique role in medicinal chemistry and have emerged as privileged pharmacophores in proteasome inhibitors. Additionally, they represent synthetically useful chiral building blocks in organic synthesis. Recently, CuH-catalyzed asymmetric alkene hydrofunctionalization has become a powerful tool to construct stereogenic carbon centers. In contrast, applying CuH cascade catalysis to achieve reductive 1,1-difunctionalization of alkynes remains an important, but largely unaddressed, synthetic challenge. Herein, we report an efficient strategy to synthesize <i>α</i>-aminoboronates <i>via </i>CuH-catalyzed hydroboration/hydroamination cascade of readily available alkynes. Notably, this transformation selectively delivers the desired 1,1-heterodifunctionalized product in favor of alternative homodifunctionalized, 1,2-heterodifunctionalized, or reductively monofunctionalized byproducts, thereby offering rapid access to these privileged scaffolds with high chemo-, regio- and enantioselectivity.<br>


2019 ◽  
Author(s):  
Victor Bloemendal ◽  
Floris P. J. T. Rutjes ◽  
Thomas J. Boltje ◽  
Daan Sondag ◽  
Hidde Elferink ◽  
...  

<p>In this manuscript we describe a modular pathway to synthesize biologically relevant (–)-<i>trans</i>-Δ<sup>8</sup>-THC derivatives, which can be used to modulate the pharmacologically important CB<sub>1</sub> and CB<sub>2</sub> receptors. This pathway involves a one-pot Friedel-Crafts alkylation/cyclization protocol, followed by Suzuki-Miyaura cross-coupling reactions and gives rise to a series of new Δ<sup>8</sup>-THC derivatives. In addition, we demonstrate using extensive NMR evidence that similar halide-substituted Friedel-Crafts alkylation/cyclization products in previous articles were wrongly assigned as the para-isomers, which also has consequence for the assignment of the subsequent cross-coupled products and interpretation of their biological activity. </p> <p>Considering the importance of the availability of THC derivatives in medicinal chemistry research and the fact that previously synthesized compounds were wrongly assigned, we feel this research is describing a straightforward pathway into new cannabinoids.</p>


2020 ◽  
Vol 11 (37) ◽  
pp. 10047-10060
Author(s):  
Christopher B. Kelly ◽  
Rosaura Padilla-Salinas

Three unrelated cationic groups, which can replace C–H bonds late stage, have been identified as progenitors to various functional groups. This review discusses the chemistry of these salts and their potential application in medicinal chemistry.


2020 ◽  
Author(s):  
Tobias Brandhofer ◽  
Volker Derdau ◽  
María Mendez ◽  
Christoph Pöverlein ◽  
Olga Garcia Mancheno

Abstract Visible light mediated late-stage functionalization is a rising field in synthetic and medicinal chemistry, allowing the fast and diversified modification of valuable, potentially therapeutic compounds such as peptides. However, there are relatively few mild methodologies for the C(sp3)-H functionalization of complex peptides. Herein, we report a visible light mediated photocatalytic protocol for the benzylic C-H modification of tyrosine and related C-H bonds. The embraced radical-cation/deprotonation strategy enables an incorporation of a wide range of valuable functional groups in high yields and chemoselectivity. The mild reaction conditions, site-selectivity and high functional group tolerance was highlighted by the functionalization of complex peptides, drugs and natural products, providing a promising synthetic platform in medicinal chemistry.


2020 ◽  
Vol 26 (34) ◽  
pp. 7678-7684 ◽  
Author(s):  
Henry Robinson ◽  
Steven A. Oatley ◽  
James E. Rowedder ◽  
Pawel Slade ◽  
Simon J. F. Macdonald ◽  
...  
Keyword(s):  

2021 ◽  
Author(s):  
Luca Capaldo ◽  
Stefano Bonciolini ◽  
Antonio Pulcinella ◽  
Manuel Nuno ◽  
Timothy Noel

The late-stage introduction of allyl groups provides an opportunity to synthetic organic chemists for subsequent diversification, providing rapid access to new chemical space. Here, we report the development of a modular synthetic sequence for the allylation of strong aliphatic C(sp3)–H bonds. Our sequence features the merger of two distinct steps to accomplish this goal, including a photocatalytic Hydrogen Atom Transfer and an ensuing Horner-Wadsworth-Emmons reaction. This practical protocol enables the modular and scalable allylation of valuable building blocks and medicinally relevant molecules.


2021 ◽  
Vol 25 ◽  
Author(s):  
Paolo Ronchi ◽  
Sara Guariento ◽  
Daniele Pala ◽  
Daniela Pizzirani ◽  
Claudio Fiorelli ◽  
...  

: The use of F-based decorations in drug discovery started from the development of fluorocorticoids and fluorochinolones (1950s and 1980s, respectively), and has resulted in about 20% of approved drugs on the Market containing fluorine. From a medicinal chemistry perspective, the installation of F-based small groups (e.g., CF3, -CF2H, -OCF3, -OCF2H, -SCF3, -SCF2H) necessarily impacts on physicochemical, pharmacokinetics, pharmacodynamics and toxicological properties of small molecules. Accordingly, a huge interest in this topic is constantly arising in the medicinal chemistry community. Focusing on heteroarenes, the synthetic access to these substitutions is guaranteed by a number of effective reactions such as Minisci-type reaction, photochemistry or electrochemistry C-H activation. The aim of this work is to analyze the rationale in using these groups in medicinal chemistry and highlight the currently available synthetic toolbox of C-H activation for their introduction on heteroarenes of pharmaceutical interest. A particular focus has been given to those procedures amenable to the late-stage functionalisation process.


2018 ◽  
Vol 9 (12) ◽  
pp. 3215-3220 ◽  
Author(s):  
James P. Phelan ◽  
Rebecca J. Wiles ◽  
Simon B. Lang ◽  
Christopher B. Kelly ◽  
Gary A. Molander

Herein describes two complementary methods, a one-step cross-coupling and the functionalization of a ‘masked’ functionality, to access diverse trifluoromethyl alkenes.


Molecules ◽  
2019 ◽  
Vol 24 (22) ◽  
pp. 4143
Author(s):  
Tamie Suzuki ◽  
Nilamber A. Mate ◽  
Arijit A. Adhikari ◽  
John D. Chisholm

2-Substituted indoles may be directly transformed to 3,3-dialkyl indolenines with trichloroacetimidate electrophiles and the Lewis acid TMSOTf. These reactions provide rapid access to complex indolenines which are present in a variety of complex natural products and medicinally relevant small molecule structures. This method provides an alternative to the use of transition metal catalysis. The indolenines are readily transformed into spiroindoline systems which are privileged scaffolds in medicinal chemistry.


Synlett ◽  
2019 ◽  
Vol 31 (03) ◽  
pp. 199-204 ◽  
Author(s):  
Zengbing Bai ◽  
Huan Wang

Peptide macrocycles are widely used in fields ranging from medicinal chemistry to materials science. Efficient chemical methods for the synthesis of cyclic peptides with novel three-dimensional structures are highly desired to facilitate the development of this unique class of compounds. However, the range of methods available for constructing peptide macrocycles is limited compared with that for small molecules. We recently developed new methods for synthesizing highly constrained cyclic peptides with C–C crosslinks through Pd-catalyzed C–H activation reactions. These methods use endogenous backbone amides as directing groups and, therefore, have the potential for use in late-stage functionalization of peptide natural products.


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