Reduction of Ketones to Alkenes

Chamberlin, A. Richard; Sall, Daniel J.

doi:10.1016/b978-0-08-052349-1.00251-1

Cited by 11 publications

(4 citation statements)

References 180 publications

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“…Morpholine, for example, is acylated by 3,4,5-trimethoxybenzoyl chloride to form the tranquilizer and muscle relaxant [11]; already Nmethyl piperazine can be alkylated in an SN1 reaction with diphenyl methyl chloride to obtain cyclizine as a product [12], seasickness medicine. The addition of pyrrolidine to an aldehyde or ketone forms a product that belongs to the class of enamines, which is very important in the chemistry of heterocycles because it has broad applicability as precursors in the synthesis of both synthetic and natural organic compounds [13], [14].…”

Section: A Nitrogen Heterocyclementioning

confidence: 99%

Microbial Degradation of Heterocycles- A Review

Da Silva Martins,

Rodrigues Barbosa,

Baleixo da Silva

et al. 2023

JSSE

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Heterocycles are organic compounds that are well-known and distributed in nature; they can be used in the pharmaceutical, agrochemical, and chemical industries. Heterocycles composed of sulfur, nitrogen, and oxygen atoms are harmful toxins and can cause cancers; these substances can persist for years in the environment. One attractive alternative to expensive physical and chemical methods is microbial degradations, which present high potential and low cost, causing minimal environmental impacts. The use of these microorganisms makes use of heterocyclic substances as substrates, removing them efficiently and safely. Some strains of wild and genetically modified microorganisms (bacteria and fungi) have already been used to degrade various pesticides and aromatic compounds. Understanding the biodegradation mechanism of microorganisms will benefit future bioremediation studies, which may prove to be one of the alternatives to solving environmental problems. This review will focus on the microbial degradation of heterocyclic compounds, taking into account the most used techniques and their limitations in future research

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Section: A Nitrogen Heterocyclementioning

confidence: 99%

Microbial Degradation of Heterocycles- A Review

Da Silva Martins,

Rodrigues Barbosa,

Baleixo da Silva

et al. 2023

JSSE

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“…The traditional pathway to generate the unsaturation in carbonyl compounds involved the enolate or enamine chemistry (Fig. 1a) [1][2][3][4][5][6][7][8][9][10][11] . Later, the classical enolate chemistry was superseded by transition metal catalysis.…”

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confidence: 99%

Tandem dehydrogenation-olefination-decarboxylation of cycloalkyl carboxylic acids via multifold C–H activation

Pal,

Ghosh,

Islam

et al. 2024

Nat Commun

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Dehydrogenation chemistry has long been established as a fundamental aspect of organic synthesis, commonly encountered in carbonyl compounds. Transition metal catalysis revolutionized it, with strategies like transfer-dehydrogenation, single electron transfer and C–H activation. These approaches, extended to multiple dehydrogenations, can lead to aromatization. Dehydrogenative transformations of aliphatic carboxylic acids pose challenges, yet engineered ligands and metal catalysis can initiate dehydrogenation via C–H activation, though outcomes vary based on substrate structures. Herein, we have developed a catalytic system enabling cyclohexane carboxylic acids to undergo multifold C–H activation to furnish olefinated arenes, bypassing lactone formation. This showcases unique reactivity in aliphatic carboxylic acids, involving tandem dehydrogenation-olefination-decarboxylation-aromatization sequences, validated by control experiments and key intermediate isolation. For cyclopentane carboxylic acids, reluctant to aromatization, the catalytic system facilitates controlled dehydrogenation, providing difunctionalized cyclopentenes through tandem dehydrogenation-olefination-decarboxylation-allylic acyloxylation sequences. This transformation expands carboxylic acids into diverse molecular entities with wide applications, underscoring its importance.

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“…For example, 17 underwent a nucleophilic ring opening/elimination sequence with morpholine to give aminophototropone 18 , and similar reactions with other nucleophiles could easily be envisaged. Epoxyketone 17 also undergoes Wharton transposition 18 upon exposure to hydrazine under acidic conditions, generating epi - 9 —a diastereoisomer of the major product obtained via direct reduction of 1 using DIBAL-H.…”

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confidence: 99%