Cobalt(III)-Catalyzed 1,4-Addition of C(sp3)–H Bonds to Maleimides

Synlett ◽  
2018 ◽  
Vol 29 (12) ◽  
pp. 1601-1606 ◽  
Author(s):  
Meng Sun ◽  
Xiang-Xiang Chen ◽  
Jiang-Tao Ren ◽  
Jing-Lei Xu ◽  
Hu Xie ◽  
...  
Keyword(s):  
Natural Products ◽  
Functional Groups ◽  
Crucial Role ◽  
Addition Reactions ◽  
Alkylation Reactions

Quinolines and succinimides play a crucial role in many pharmaceutical and natural products. Although sp2 C–H bond addition reactions have been extensively investigated, Co(III)-catalyzed sp3 C–H bond 1,4-addition reactions are relatively unexplored. In this manuscript, an efficient and atom-economic protocol for alkylation reactions of 8-methylquinolines with maleimides is presented. The reaction exhibits exceptional reactivity, satisfactory yields, excellent chemo- and regioselectivity, and tolerates a variety of functional groups.

Copper Catalyzed sp3 C-H α-Acetylation

2019 ◽  
Author(s):  
Otome Okoromoba ◽  
Eun Sil Jang ◽  
Claire McMullin ◽  
Thomas Cundari ◽  
Timothy H. Warren
Keyword(s):  
Natural Products ◽  
Dft Studies ◽  
Alkyl Radicals ◽  
Important Chemical ◽  
Alkyl Electrophiles ◽  
Synthetic Intermediates ◽  
Alkylation Reactions

<p>α-substituted ketones are important chemical targets as synthetic intermediates as well as functionalities in in natural products and pharmaceuticals. We report the sp<sup>3</sup> C-H α-acetylation of sp<sup>3</sup> C-H substrates R-H with arylmethyl ketones ArC(O)Me to provide α-alkylated ketones ArC(O)CH<sub>2</sub>R at RT with <sup>t</sup>BuOO<sup>t</sup>Bu as oxidant via copper(I) β-diketiminato catalysts. Proceeding via alkyl radicals R•, this method enables α-substitution with bulky substituents without competing elimination that occurs in more traditional alkylation reactions between enolates and alkyl electrophiles. DFT studies suggest the intermediacy of copper(II) enolates [Cu<sup>II</sup>](CH<sub>2</sub>C(O)Ar) that capture alkyl radicals R• to give R-CH<sub>2</sub>C(O)Ar under competing dimerization of the copper(II) enolate to give the 1,4-diketone ArC(O)CH<sub>2</sub>CH<sub>2</sub>C(O)Ar.</p>

Copper Catalyzed sp3 C-H α-Acetylation

2019 ◽  
Author(s):  
Otome Okoromoba ◽  
Eun Sil Jang ◽  
Claire McMullin ◽  
Thomas Cundari ◽  
Timothy H. Warren
Keyword(s):  
Natural Products ◽  
Dft Studies ◽  
Alkyl Radicals ◽  
Important Chemical ◽  
Alkyl Electrophiles ◽  
Synthetic Intermediates ◽  
Alkylation Reactions

<p>α-substituted ketones are important chemical targets as synthetic intermediates as well as functionalities in in natural products and pharmaceuticals. We report the sp<sup>3</sup> C-H α-acetylation of sp<sup>3</sup> C-H substrates R-H with arylmethyl ketones ArC(O)Me to provide α-alkylated ketones ArC(O)CH<sub>2</sub>R at RT with <sup>t</sup>BuOO<sup>t</sup>Bu as oxidant via copper(I) β-diketiminato catalysts. Proceeding via alkyl radicals R•, this method enables α-substitution with bulky substituents without competing elimination that occurs in more traditional alkylation reactions between enolates and alkyl electrophiles. DFT studies suggest the intermediacy of copper(II) enolates [Cu<sup>II</sup>](CH<sub>2</sub>C(O)Ar) that capture alkyl radicals R• to give R-CH<sub>2</sub>C(O)Ar under competing dimerization of the copper(II) enolate to give the 1,4-diketone ArC(O)CH<sub>2</sub>CH<sub>2</sub>C(O)Ar.</p>

scholarly journals Non-Enzymatic Desymmetrization Reactions in Aqueous Media

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 720
Author(s):  
Satomi Niwayama
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Functional Groups ◽  
Organic Compounds ◽  
Recent Progress ◽  
Aqueous Media ◽  
Building Blocks ◽  
Organic Reactions ◽  
Environmentally Benign ◽  
Enzymatic Desymmetrization

Symmetric organic compounds are generally obtained inexpensively, and therefore they can be attractive building blocks for the total synthesis of various pharmaceuticals and natural products. The drawback is that discriminating the identical functional groups in the symmetric compounds is difficult. Water is the most environmentally benign and inexpensive solvent. However, successful organic reactions in water are rather limited due to the hydrophobicity of organic compounds in general. Therefore, desymmetrization reactions in aqueous media are expected to offer versatile strategies for the synthesis of a variety of significant organic compounds. This review focuses on the recent progress of desymmetrization reactions of symmetric organic compounds in aqueous media without utilizing enzymes.

A chemoinformatic analysis of atoms, scaffolds and functional groups in natural products

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Joelle Ngo Hanna ◽  
Boris D. Bekono ◽  
Luc C. O. Owono ◽  
Flavien A. A. Toze ◽  
James A. Mbah ◽  
...  
Keyword(s):  
Natural Products ◽  
Drug Discovery ◽  
Physicochemical Properties ◽  
Functional Groups ◽  
Atomic Composition ◽  
Synthetic Compounds ◽  
Chemical Libraries ◽  
Synthetic Drugs ◽  
Drugs Analysis ◽  
Chemical Class

Abstract In the quest to know why natural products (NPs) have often been considered as privileged scaffolds for drug discovery purposes, many investigations into the differences between NPs and synthetic compounds have been carried out. Several attempts to answer this question have led to the investigation of the atomic composition, scaffolds and functional groups (FGs) of NPs, in comparison with synthetic drugs analysis. This chapter briefly describes an atomic enumeration method for chemical libraries that has been applied for the analysis of NP libraries, followed by a description of the main differences between NPs of marine and terrestrial origin in terms of their general physicochemical properties, most common scaffolds and “drug-likeness” properties. The last parts of the work describe an analysis of scaffolds and FGs common in NP libraries, focusing on huge NP databases, e.g. those in the Dictionary of Natural Products (DNP), NPs from cyanobacteria and the largest chemical class of NP – terpenoids.

Balancing skeleton and functional groups in total syntheses of complex natural products: a case study of tigliane, daphnane and ingenane diterpenoids

2021 ◽  
Author(s):  
Zhi Liu ◽  
Zhengwei Ding† ◽  
Kai Chen ◽  
Ming Xu ◽  
Tao Yu ◽  
...  
Keyword(s):  
Natural Products ◽  
Functional Groups ◽  
Synthetic Chemistry ◽  
Total Syntheses ◽  
Strategic Balance

The fruitful advancement in synthetic chemistry of the title families of complex diterpenes has stimulated and enjoyed strategic balance between building the skeletons and installing the functional groups.

Oxidative cyclization for the synthesis of complex tetrahydrofuran-containing natural products

2013 ◽  
Vol 85 (6) ◽  
pp. 1175-1184 ◽  
Author(s):  
Robert D. C. Pullin ◽  
Radosław M. Lipiński ◽  
Timothy J. Donohoe
Keyword(s):  
Natural Products ◽  
Amino Acid ◽  
Functional Groups ◽  
Lewis Acid ◽  
Excitatory Amino Acid ◽  
Oxidative Cyclization ◽  
Annonaceous Acetogenins ◽  
Hydride Shift ◽  
Vicinal Diols ◽  
Shift Sequence

The osmium-catalyzed oxidative cyclization of vicinal diols onto proximal olefins to generate 2,5-cis-substituted tetrahydrofurans (THFs) has been exploited as the key step for the construction of several complex THF-containing natural products, namely, the annonaceous acetogenins cis-sylvaticin, sylvaticin, and the excitatory amino acid neo-dysiherbaine A. Recently modified conditions that employ a Lewis acid enable the cyclization to proceed under milder conditions, providing greater tolerance to acid-sensitive functional groups, as demonstrated in two of the syntheses. Flexibility for the construction of 2,5-trans-THFs was demonstrated in the synthesis of sylvaticin by utilization of an intramolecular hydride-shift sequence.

2 A chemoinformatic analysis of atoms, scaffolds and functional groups in natural products

2021 ◽  
pp. 31-56
Author(s):  
Joelle Ngo Hanna ◽  
Boris D. Bekono ◽  
Luc C. O. Owono ◽  
Flavien A. A. Toze ◽  
James A. Mbah ◽  
...  
Keyword(s):  
Natural Products ◽  
Functional Groups

scholarly journals Anti-selective [3+2] (Hetero)annulation of non-conjugated alkenes via directed nucleopalladation

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Hui-Qi Ni ◽  
Ilia Kevlishvili ◽  
Pranali G. Bedekar ◽  
Joyann S. Barber ◽  
Shouliang Yang ◽  
...  
Keyword(s):  
Natural Products ◽  
Functional Groups ◽  
Oxidative Addition ◽  
Reductive Elimination ◽  
Direct Access ◽  
Computational Studies ◽  
Preliminary Results ◽  
Carbon Based

Abstract2,3-Dihydrobenzofurans and indolines are common substructures in medicines and natural products. Herein, we describe a method that enables direct access to these core structures from non-conjugated alkenyl amides and ortho-iodoanilines/phenols. Under palladium(II) catalysis this [3 + 2] heteroannulation proceeds in an anti-selective fashion and tolerates a wide variety of functional groups. N-Acetyl, -tosyl, and -alkyl substituted ortho-iodoanilines, as well as free –NH2 variants, are all effective. Preliminary results with carbon-based coupling partners also demonstrate the viability of forming indane core structures using this approach. Experimental and computational studies on reactions with phenols support a mechanism involving turnover-limiting, endergonic directed oxypalladation, followed by intramolecular oxidative addition and reductive elimination.

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