Regioselective synthesis of piperidinones by metal-catalyzed ring expansion-carbonylation reactions. Remarkable cobalt and/or ruthenium carbonyl catalyzed rearrangement and cyclization reactions

Recent development in the transition metal-catalyzed cyclization reactions for organic syntheses in the author's laboratories is summarized, which includes (i) novel silylcarbocyclizations (SiCaCs) and carbonylative carbotricyclizations, (ii) intramolecular silylformylations and desymmerization of siloxydiynes by sequential double silylformylation, (iii) efficient total synthesis of (+)-prosopinine, (iv) enantioselective desymmetrization of aminodienes, and (iv) new and efficient routes to 1-azabicyclo[x.y.0]alkane amino acids. All these processes are catalyzed by Rh or RhCo complexes, and useful for rapid and efficient construction of a variety of heterocyclic and carbocyclic compounds. Mechanisms of these new carbocyclization and cyclohydrocarbonylation reactions are also discussed.

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Regioselective Synthesis of α,α-Difluorocyclopentanone Derivatives: Domino Nickel-Catalyzed Difluorocyclopropanation/Ring-Expansion Sequence of Silyl Dienol Ethers

Organic Letters ◽

10.1021/acs.orglett.5b02726 ◽

2015 ◽

Vol 17 (23) ◽

pp. 5736-5739 ◽

Cited By ~ 19

Author(s):

Tatsuya Aono ◽

Hisashi Sasagawa ◽

Kohei Fuchibe ◽

Junji Ichikawa

Keyword(s):

Ring Expansion ◽

Regioselective Synthesis

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Synthesis, Structure and In Vitro Cytotoxic Activity of Novel Cinchona—Chalcone Hybrids with 1,4-Disubstituted- and 1,5-Disubstituted 1,2,3-Triazole Linkers

Molecules ◽

10.3390/molecules24224077 ◽

2019 ◽

Vol 24 (22) ◽

pp. 4077 ◽

Cited By ~ 3

Author(s):

Jernei ◽

Duró ◽

Dembo ◽

Lajkó ◽

Takács ◽

...

Keyword(s):

Cytotoxic Activity ◽

Malignant Cell ◽

Conformational Space ◽

In Vitro Assays ◽

Inhibitory Effects ◽

Cyclization Reactions ◽

Click Reactions ◽

Metal Catalyzed ◽

Dft Modelling

By means of copper(I)-and ruthenium(II)-catalyzed click reactions of quinine- and quinidine-derived alkynes with azide-substituted chalcones a systematic series of novel cinchona-chalcone hybrid compounds, containing 1,4-disubstituted- and 1,5-disubstituted 1,2,3-triazole linkers, were synthesized and evaluated for their cytotoxic activity on four human malignant cell lines (PANC-1, COLO-205, A2058 and EBC-1). In most cases, the cyclization reactions were accompanied by the transition-metal-catalyzed epimerization of the C9-stereogenic centre in the cinchona fragment. The results of the in vitro assays disclosed that all the prepared hybrids exhibit marked cytotoxicity in concentrations of low micromolar range, while the C9-epimerized model comprising quinidine- and (E)-1-(4-(3-oxo-3-(3,4,5-trimethoxyphenyl)prop-1-en-1-yl)phenyl) fragments, connected by 1,5-disubstituted 1,2,3-triazole linker, and can be regarded as the most potent lead of which activity is probably associated with a limited conformational space allowing for the adoption of a relatively rigid well-defined conformation identified by DFT modelling. The mechanism of action of this hybrid along with that of a model with markedly decreased activity were approached by comparative cell-cycle analyses in PANC-1 cells. These studies disclosed that the hybrid of enhanced antiproliferative activity exerts significantly more extensive inhibitory effects in subG1, S and G2/M phases than does the less cytotoxic counterpart.

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Stereoselective and Regioselective Synthesis of Azepane and Azepine Derivatives via Piperidine Ring Expansion.

ChemInform ◽

10.1002/chin.200308157 ◽

2003 ◽

Vol 34 (8) ◽

Author(s):

Hyun-soon Chong ◽

Bishwajit Ganguly ◽

Grant A. Broker ◽

Robin D. Rogers ◽

Martin W. Brechbiel

Keyword(s):

Ring Expansion ◽

Regioselective Synthesis ◽

Piperidine Ring

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Recent Advances in Photocatalytic C–N Bond Coupling Reactions

Synthesis ◽

10.1055/s-0040-1707136 ◽

2020 ◽

Author(s):

Wing-Yiu Yu ◽

Chun-Ming Chan ◽

Yip-Chi Chow

Keyword(s):

Carbonyl Compounds ◽

Bond Formation ◽

Coupling Reactions ◽

Amino Groups ◽

Cyclization Reactions ◽

Radical Coupling ◽

Synthetic Intermediates ◽

Photocatalytic Reactions ◽

Metal Catalyzed ◽

Pharmaceutical Agents

Catalytic C–N bond formation is one of the major research topics in synthetic chemistry owing to the ubiquity of amino groups in natural products, synthetic intermediates and pharmaceutical agents. In parallel with well-established metal-catalyzed C–N bond coupling protocols, photocatalytic reactions have recently emerged as efficient and selective alternatives for the construction of C–N bonds. In this review, the progress made on photocatalytic C–N bond coupling reactions between 2012 and February 2020 is summarized.1 Introduction1.1 General Mechanisms for Photoredox Catalysis1.2 Pioneering Work2 C(sp2)–N Bond Formation2.1 Protocols Involving an External Oxidant2.2 Oxidant-Free Protocols3 C(sp3)–N Bond Formation3.1 Direct Radical–Radical Coupling3.2 Addition Reactions to Alkenes3.3 Reductive Amination of Carbonyl Compounds3.4 Decarboxylative Amination4 Cyclization Reactions4.1 C(sp2)–N Heterocycle Formation4.2 C(sp3)–N Heterocycle Formation5 Other Examples6 Conclusion and Outlook

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