Recent advances in acyl radical enabled reactions between aldehydes and alkenes
TL;DR: A summary of the state of the art in this field with a specific emphasis on the working models and corresponding mechanisms is provided in this paper, where the discussion is divided according to the kind of alkenes and reaction type.
About: This article is published in Chemical Communications.The article was published on 2021-06-22. It has received 23 citations till now.
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TL;DR: NHC and visible light-mediated photoredox co-catalyzed radical 1,4-sulfonylacylation of 1,3-enynes is described, providing structurally diversified valuable tetrasubstituted allenyl ketones and highly selective cross-coupling of an acyl radical with an alkyl radical for efficient construction of C–C bonds.
Abstract: The modulation of selectivity of highly reactive carbon radical cross-coupling for the construction of C–C bonds represents a challenging task in organic chemistry. N-Heterocyclic carbene (NHC) catalyzed radical transformations have opened a new avenue for acyl radical cross-coupling chemistry. With this method, highly selective cross-coupling of an acyl radical with an alkyl radical for efficient construction of C–C bonds was successfully realized. However, the cross-coupling reaction of acyl radicals with vinyl radicals has been much less investigated. We herein describe NHC and visible light-mediated photoredox co-catalyzed radical 1,4-sulfonylacylation of 1,3-enynes, providing structurally diversified valuable tetrasubstituted allenyl ketones. Mechanistic studies indicated that ketyl radicals are formed from aroyl fluorides via the oxidative quenching of the photocatalyst excited state, allenyl radicals are generated from chemo-specific sulfonyl radical addition to the 1,3-enynes, and finally, the key allenyl and ketyl radical cross-coupling provides tetrasubstituted allenyl ketones.
24 citations
TL;DR: In this article , a photocatalytic protocol for the synthesis of β-amino acid ester and βamino ketone derivatives is developed by using simple and easy-to-synthesize oxime oxalate and oxime phenylglyoxylate as difunctionalization reagents.
Abstract: A photocatalytic protocol for the synthesis of β-amino acid ester and β-amino ketone derivatives is developed by using simple and easy-to-synthesize oxime oxalate and oxime phenylglyoxylate as difunctionalization reagents. These...
20 citations
TL;DR: In this paper, an unprecendented dearomatization of biaryl ynones with aldehydes via double C-H functionalization was reported, where a regiospecific remote unactivated para-C-H function was used to efficiently furnishes acylated spiro[5.5]trienones.
Abstract: The multiple C-H bonds of biaryl ynones render the 6-exo-trig regioselective C-H activation dearomatization to spiro[5.5]trienones challenging since the competing reactions of C-H bonds on Ar1 or the ortho-C-H bonds on Ar3 may result in 5-exo-trig cyclization to indenones or 6-exo-trig ortho-dearomatization, respectively. We here report an unprecendented dearomatization of biaryl ynones with aldehydes via double C-H functionalization where a regiospecific remote unactivated para-C-H functionalization of biaryl ynones efficiently furnishes acylated spiro[5.5]trienones. This cascade cyclization features a green catalyst and solvent and high atom- and step-economy.
13 citations
TL;DR: DMP plays dual roles in mediating the free radical thiocyanation and inducing the unconventional selective thiazole-5-carbaldehyde formation by masking the in situ generated formyl group during the reaction process.
Abstract: The Dess-Martin periodinane (DMP) reagent-mediated reactions of tertiary enaminones with potassium thiocyanate for the synthesis of thiazole-5-carbaldehydes are developed. The product formation involves cascade hydroxyl thiocyanation of the C═C double bond, intramolecular hydroamination of the C≡N bond, and thiazole annulation by condensation on the ketone carbonyl site, representing novel reaction pathways in the reactions between enaminones and thiocyanate salt. DMP plays dual roles in mediating the free radical thiocyanation and inducing the unconventional selective thiazole-5-carbaldehyde formation by masking the in situ generated formyl group during the reaction process.
6 citations
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3,181 citations
TL;DR: This work over the past several years to form carbon-carbon bonds directly from two different C-H bonds under oxidative conditions, cross-dehydrogenative coupling (CDC) is described, which provides an alternative to the separate steps of prefunctionalization and defunctionsalization that have traditionally been part of synthetic design.
Abstract: Synthetic chemists aspire both to develop novel chemical reactions and to improve reaction conditions to maximize resource efficiency, energy efficiency, product selectivity, operational simplicity, and environmental health and safety. Carbon−carbon bond formation is a central part of many chemical syntheses, and innovations in these types of reactions will profoundly improve overall synthetic efficiency. This Account describes our work over the past several years to form carbon−carbon bonds directly from two different C−H bonds under oxidative conditions, cross-dehydrogenative coupling (CDC). We have focused most of our efforts on carbon−carbon bonds formed via the functionalization of sp3 C−H bonds with other C−H bonds. In the presence of simple and cheap catalysts such as copper and iron salts and oxidants such as hydrogen peroxide, dioxygen, tert-butylhydroperoxide, and 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ), we can directly functionalize various sp3 C−H bonds by other C−H bonds without requiring ...
2,308 citations
TL;DR: This critical review covers the recent progresses on the regioselective dehydrogenative direct coupling reaction of heteroarenes, including arylation, olefination, alkynylation, and amination/amidation mainly utilizing transition metal catalysts.
Abstract: The direct functionalization of heterocyclic compounds has emerged as one of the most important topics in the field of metal-catalyzed C–H bond activation due to the fact that products are an important synthetic motif in organic synthesis, the pharmaceutical industry, and materials science. This critical review covers the recent progresses on the regioselective dehydrogenative direct coupling reaction of heteroarenes, including arylation, olefination, alkynylation, and amination/amidation mainly utilizing transition metal catalysts (113 references).
2,062 citations
TL;DR: Oxidative X-X Bond Formations between Two Nucleophiles 1819 5.1.
Abstract: 3.1. C-M and X-H as Nucleophiles 1806 3.2. C-H and X-M as Nucleophiles 1809 3.2.1. C-Halogen Bond Formations 1809 3.2.2. C-O Bond Formations 1812 3.3. C-H and X-H as Nucleophiles 1812 3.3.1. C-O Bond Formations 1812 3.3.2. C-N Bond Formations 1815 4. Oxidative X-X Bond Formations between Two Nucleophiles 1819 5. Conclusions 1819 Author Information 1819 Biographies 1819 Acknowledgment 1820 References 1820
1,564 citations
1,017 citations