Mechanism and stereoselectivity in metal and enzyme catalyzed carbene insertion into X–H and C(sp²)–H bonds

Chemical Society Reviews, Journal Year: 2024, Volume and Issue: 53(22), P. 11004 - 11044

Published: Jan. 1, 2024

This review provides a mechanistic overview of asymmetric Fe, Cu, Pd, Rh, Au and heme-based enzymes catalyzed carbene insertion reactions to construct C–X (X = O, N, S, etc. ) C–C bonds, focusing on the stereochemical models.

Language: Английский

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A combined experimental and computational study reveals a crossover between conventional cross-coupling and carbene insertion pathways in a Pd catalyzed C(sp²)–H insertion

Chemical Science, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

Computational (DFT and DLPNO-CCSD(T)) calculations along with experimental tools (deuterium labelling, kinetic studies using VTNA, ESI-HRMS UV) are used to probe the mechanism of a Pd(ii)-catalyzed enantioselective carbene insertion into C(sp2)-H indole. Using deuterium labelling studies, we demonstrate intermediacy metal-hydride species, which contrasts mechanistic routes for other transition metals (Rh, Fe, Au, Cu, etc.). Our VTNA study reveals order be one in both diazo indole, microkinetic modelling aligns well computationally predicted mechanism. The is further supported by detection most stable intermediate catalytic cycle ESI-HRMS. An investigation origin stereoselectivity DLPNO-CCSD(T) presents new paradigm, wherein stereocontrol arises during formation Pd itself as opposed proton transfer steps found all metal catalysts.

Language: Английский

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Calcium‐Catalyzed Multicomponent Reactions in Organic Synthesis

Asian Journal of Organic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: April 19, 2025

Abstract Calcium catalysis has garnered significant attention from synthetic organic chemists as a sustainable alternative to Lewis acidic transition metals, rare‐earth and strong Brønsted acids. This alkaline earth metal, abundant in nature, environmentally benign, moisture‐tolerant, biodegradable, low toxicity, offers distinct advantages. catalysts exhibit exceptional proficiency activating diverse functional groups, particularly π‐activated species such ketones, alcohols, enamines, aldehydes, alkenes, alkynes, allenes, thereby enabling nucleophilic additions tandem chemical transformations. These characteristics resonate with the core tenets of green chemistry, enhancing atom step economy while minimizing waste generation. review presents thorough in‐depth analysis calcium‐catalyzed multi‐component reactions (MCRs), underscoring their transformative role advancing synthesis. Furthermore, it explores untapped potential calcium broadening horizons MCRs, fostering innovative eco‐friendly methodologies for applications pharmaceuticals materials science. Key challenges future prospects within this evolving domain are also critically examined.

Language: Английский

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Divergent Reactions of α-Diazo 1,3-Dicarbonyl Compounds with Allylic Carbonates Involving Ketene versus Carbene Intermediates Enabled by Cooperative Rh(II)/Pd(0) Dual Catalysis

Organic Letters, Journal Year: 2024, Volume and Issue: 26(37), P. 7920 - 7925

Published: Sept. 9, 2024

A cooperative Rh(II)/Pd(0) dual-catalysis strategy that enabled divergent reactions of α-diazo 1,3-dicarbonyl compounds with allylic carbonates involving ketene versus carbene intermediates is described. The efficient synthesis α-quaternary allylated β-keto-esters was accomplished by the alkylation compounds. Alternatively, an unprecedented (1+4) annulation 2-(hydroxymethyl)allyl via dual catalysis also successfully developed, affording a wide variety tetrahydrofurans in good to high yields.

Language: Английский

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Three‐component allylic alkylation reaction of α‐diazo ketones with water and allyl carbonates for construction of homoallylic alcohols

Advanced Synthesis & Catalysis, Journal Year: 2024, Volume and Issue: 366(17), P. 3616 - 3623

Published: June 20, 2024

Abstract A three‐component allylic alkylation reaction of α‐diazo ketones, water and allyl carbonate under the cooperative catalysis Rh 2 (OAc) 4 , Pd (dba) 3 Brønsted acid was disclosed. This method provides an expeditious access to α‐keto homoallylic alcohols in good high yields. Controlled experiments support that transformations proceed through cross‐interception two active intermediates Pd‐allyl species enol derived from oxonium ylides. Moreover, synthetic generated products enable creation motifs enriched with dense functional groups, underscoring their potential as valuable building blocks.

Language: Английский

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Cesium and Phenoxide Interaction Enabled by Rh Overrides the Innate Solvent-Mediated Chemoselectivity

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(16), P. 12351 - 12358

Published: Aug. 5, 2024

DLPNO-CCSD(T) calculations are carried out to understand the distinctive chemoselectivity in a Rh(II)-catalyzed carbene insertion into C(sp2)–H bond unprotected phenols without preinstalled directing groups. As per conventional rules of solvation and separated ion pair polar aprotic solvents like acetonitrile, reaction should have resulted an O–H insertion. However, our reveal transition state model that helps overriding innate acetonitrile. It involves explicit participation added Cs2CO3 base, where interaction between phenoxide oxygen Cs cation, but not as metal-bound phenoxide, is crucial for controlling chemoselectivity. Our study will be helpful developing further reactions with broad catalyst, substrate, solvent scope.

Language: Английский

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