Photocatalyzed Dowd-Beckwith radical-polar crossover reaction for the synthesis of medium-sized carbocyclic compounds

Article Chemistry, Multidisciplinary

Divergent Total Syntheses of (-)-Crinipellins Facilitated by a HAT-Initiated Dowd-Beckwith Rearrangement

Yifan Zhao et al.

Summary: A new method has been developed for the efficient assembly of diversely functionalized polyquinane frameworks, leading to asymmetric total syntheses of various tetraquinane natural products in a concise and divergent manner.

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY (2022)

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Article Chemistry, Multidisciplinary

Control of Redox-Active Ester Reactivity Enables a General Cross-Electrophile Approach to Access Arylated Strained Rings

Daniel C. Salgueiro et al.

Summary: In this study, a nickel-catalyzed cross-electrophile approach was developed to couple various strained ring N-hydroxyphthalimide (NHP) esters with aryl and heteroaryl halides. This method can be run in flow and in 96-well plates, and it has significant application potential.

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION (2022)

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Review Chemistry, Organic

The synthesis of seven- and eight-membered rings by radical strategies

Xuan-Chi Yu et al.

Summary: Seven- and eight-membered rings are commonly found in natural products and drugs. Their synthesis is challenging due to transition state nonbonding interactions, torsional strains, flexible conformations, and complex multi-ring skeletons. The radical strategy, using metal-induced, oxidant-initiated, electrochemically promoted, or photoinduced systems, offers a powerful tool to overcome the limitations of poor selectivity and harsh reaction conditions. This review highlights recent advances in the synthesis of seven- and eight-membered rings and provides insights into exploring new reaction models in radical chemistry.

ORGANIC CHEMISTRY FRONTIERS (2022)

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Article Chemistry, Multidisciplinary

Radical 1,2,3-tricarbofunctionalization of α-vinyl-β-ketoesters enabled by a carbon shift from an all-carbon quaternary center

Qi Zhang et al.

Summary: In this study, we report an intermolecular, radical 1,2,3-tricarbofunctionalization of alpha-vinyl-beta-ketoesters for the purpose of building molecular complexity through one-pot multifunctionalization of alkenes. This reaction allows for expansion of the carbon ring by shifting a carbon from an all-carbon quaternary center, and enables the formation of further C-C bonds on the tertiary carbon intermediate to reconstruct a new all-carbon quaternary center. The good compatibility of functional groups ensures diverse synthetic transformations using this method. Experimental and theoretical studies suggest that the excellent diastereoselectivity is attributed to hydrogen bonding between the substrates and solvent.

CHEMICAL SCIENCE (2022)

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Review Chemistry, Applied

Visible Light Assisted Radical-Polar/Polar-Radical Crossover Reactions in Organic Synthesis

Shivani Sharma et al.

Summary: The novel concept of radical-polar crossover (RPCO) and polar-radical crossover (PRCO) reactions has emerged in recent years as a valuable tool bridging the gap between polar and radical reactions, overcoming their limitations, and improving the green quotient of reactions. The development and transformation of this area into synthetically important reactions is summarized in this review.

ADVANCED SYNTHESIS & CATALYSIS (2021)

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Article Chemistry, Multidisciplinary

Asymmetric Total Synthesis and Biosynthetic Implications of Perovskones, Hydrangenone, and Hydrangenone B

Baochao Yang et al.

Summary: Perovskones and hydrangenones are a family of structurally complex triterpenoids mainly isolated from Salvia medicinal plants, showing a wide range of biological activities such as antitumor and antiplasmodial activities. The total synthesis of these compounds involved asymmetric photoenolization/Diels-Alder reactions, bioinspired Diels-Alder reactions, and late-stage oxidations and ring forming steps. Studies suggest that perovskatone D may be a precursor for the biosynthesis of perovskones, while the formation of hydrangenone and hydrangenone B may involve an oxidative ring cleavage and ring regeneration process.

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY (2021)

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Article Chemistry, Multidisciplinary

Visible-light-driven palladium-catalyzed Dowd-Beckwith ring expansion/C-C bond formation cascade

Li Chen et al.

Summary: A visible light-induced palladium-catalyzed Dowd-Beckwith ring expansion/C-C bond formation cascade has been successfully developed to access a variety of six to nine-membered beta-alkenylated cyclic ketones with a quaternary carbon center under mild conditions. In addition to styrenes, electron-rich alkenes like silyl enol ethers and enamides are also compatible substrates, providing the desired beta-alkylated cyclic ketones in moderate to good yields.

CHEMICAL SCIENCE (2021)

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Review Chemistry, Multidisciplinary