ChemInform Abstract: The Orthoester Johnson-Claisen Rearrangement in the Synthesis of Bioactive Molecules, Natural Products, and Synthetic Intermediates - Recent Advances

ChemInform ◽  
2014 ◽  
Vol 45 (46) ◽  
pp. no-no
Author(s):  
Rodney A. Fernandes ◽  
Asim K. Chowdhury ◽  
Pullaiah Kattanguru
Author(s):  
Min Zhang ◽  
Ying Gong ◽  
Wei Zhou ◽  
Ying Zhou ◽  
Xiong-Li Liu

Chiral polycyclic chromanones are important heterocyclic frameworks that constitute the core structures of many natural products and bioactive molecules. As starting materials, the chromone-based reactants are very efficient building blocks...


2017 ◽  
Vol 15 (13) ◽  
pp. 2672-2710 ◽  
Author(s):  
Rodney A. Fernandes ◽  
Pullaiah Kattanguru ◽  
Sachin P. Gholap ◽  
Dipali A. Chaudhari

This review documents the reports since 2005 on the Overman rearrangement, an important C–N bond forming reaction that has been profoundly used in the synthesis of natural products, synthetic intermediates, building blocks and valuable compounds.


2021 ◽  
Author(s):  
G. Grace Victoria ◽  
Sabbasani Rajasekhara Reddy

Organic nitrogen–chlorine compounds and their derivatives are important heterocyclic motifs, exhibiting applications such as N-chlorinating agents, analytical reagents, disinfectants, antipathogens, and as synthetic intermediates for drugs, polymers, and natural products.


Synthesis ◽  
2020 ◽  
Author(s):  
Shrikant G. Pharande

AbstractLactams are very important heterocycles as a result of their presence in a wide range of bioactive molecules, natural products and drugs, and also due their utility as versatile synthetic intermediates. Due to these reasons, numerous efforts have focused on the development of effective and efficient methods for their synthesis. Compared to conventional two-component reactions, multicomponent reactions (MCRs), particularly isocyanide-based MCRs, are widely used for the synthesis of a range of small heterocycles including lactam analogues. Despite their numerous applications in almost every field of chemistry, as yet there is no dedicated review on isocyanide-based multicomponent reactions (IMCRs) concerning the synthesis of lactams. Therefore, this review presents strategies towards the synthesis of α-, β-, γ-, δ- and ε-lactams using IMCRs or IMCRs/post-transformation reactions reported in the literature between 2000 and 2020.1 Introduction2 Developments in Lactam Synthesis2.1 α-Lactams2.2 β-Lactams2.3 γ-Lactams2.3.1 General γ-Lactams2.3.2 Benzo-Fused γ-Lactams2.3.3 Spiro γ-Lactams2.3.4 α,β-Unsaturated γ-Lactams2.3.5 Polycyclic Fused γ-Lactams2.4 δ-Lactams2.5 ε-Lactams3 Conclusions


2019 ◽  
Author(s):  
Otome Okoromoba ◽  
Eun Sil Jang ◽  
Claire McMullin ◽  
Thomas Cundari ◽  
Timothy H. Warren

<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>


2019 ◽  
Author(s):  
Otome Okoromoba ◽  
Eun Sil Jang ◽  
Claire McMullin ◽  
Thomas Cundari ◽  
Timothy H. Warren

<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>


Author(s):  
D. H. Sreenivasa Rao ◽  
Ayon Chatterjee ◽  
Santosh Kumar Padhi

Chiral β-nitroalcohols are versatile synthetic intermediates for several pharmaceuticals, and bioactive molecules. This review describes the importance and various biocatalytic approaches for their enantio and diastereoselective synthesis.


Tetrahedron ◽  
2013 ◽  
Vol 69 (34) ◽  
pp. 6921-6957 ◽  
Author(s):  
K.C. Majumdar ◽  
Raj Kumar Nandi

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