Recent advances in transition-metal-free arylation reactions involving hypervalent iodine salts

• Ritu Mamgain,
• Kokila Sakthivel and
• Fateh V. Singh

Beilstein J. Org. Chem. 2024, 20, 2891–2920, doi:10.3762/bjoc.20.243

Copper-catalyzed yne-allylic substitutions: concept and recent developments

• Shuang Yang and
• Xinqiang Fang

Beilstein J. Org. Chem. 2024, 20, 2739–2775, doi:10.3762/bjoc.20.232

• –heteroatom bonds vicinal to alkenyl or alkynyl groups, which are highly valuable for downstream synthesis. At present, unstabilized nucleophiles [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51] are commonly used in Cu-catalyzed allylic substitutions because of the inner-sphere

Harnessing the versatility of hydrazones through electrosynthetic oxidative transformations

• Aurélie Claraz

Beilstein J. Org. Chem. 2024, 20, 1988–2004, doi:10.3762/bjoc.20.175

• that potassium iodide would serve as an electromediator to oxidize the hydrazone through an inner-sphere electron transfer. Moreover, the electrolysis proceeded more efficiently in the presence of ammonium acetate since (i) the acetate anion would serve as a base to facilitate the oxidation of the

Benzylic C(sp³)–H fluorination

• Alexander P. Atkins,
• Alice C. Dean and
• Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 1527–1547, doi:10.3762/bjoc.20.137

• was effective for the stereoselective fluorination of benzylic positions ortho to aldehyde substituents (Figure 9). The choice of a bulky amino, transient, directing group dictated the stereochemical outcome and promoted the C–F reductive elimination through an inner-sphere pathway. A competitive C–O

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• 109 would give rise to photoexcited complex 110 under blue light irradiation (Scheme 21B). Complex 110 and NHPI ester 3 would then engage in SET likely through an inner sphere mechanism, providing phthalimide ligated CuII intermediate 111 and carboxyl radical 112. At this stage, the resulting radical

Radical ligand transfer: a general strategy for radical functionalization

• David T. Nemoto Jr,
• Kang-Jie Bian,
• Shih-Chieh Kao and
• Julian G. West

Beilstein J. Org. Chem. 2023, 19, 1225–1233, doi:10.3762/bjoc.19.90

• the addition of terminal oxidant. II: The proposed mechanism includes reoxidation of the iron catalyst through inner-sphere electron transfer by anionic nitrate. Funding J.G.W. acknowledges financial support from CPRIT (RR190025), NIH NIGMS (R35GM142738), Research Corporation for Science Advancement

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

Visible-light-mediated copper photocatalysis for organic syntheses

• Yajing Zhang,
• Qian Wang,
• Zongsheng Yan,
• Donglai Ma and
• Yuguang Zheng

Beilstein J. Org. Chem. 2021, 17, 2520–2542, doi:10.3762/bjoc.17.169

• product Nu–R can be obtained through an inner-sphere pathway between [LnCuIINu]X and the radical R• [41][42] (Scheme 5A). Alternatively, a photosensitizer generated a radical via reduction or oxidation, and is not engaged in the key bond construction. [LCuI] is photoexcited to generate LnCuI*, which

Recent developments in enantioselective photocatalysis

• Callum Prentice,
• James Morrisson,
• Andrew D. Smith and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2020, 16, 2363–2441, doi:10.3762/bjoc.16.197

Photoredox-catalyzed silyldifluoromethylation of silyl enol ethers

• Vyacheslav I. Supranovich,
• Vitalij V. Levin and
• Alexander D. Dilman

Beilstein J. Org. Chem. 2020, 16, 1550–1553, doi:10.3762/bjoc.16.126

• strongly reducing catalysts may be associated with the ability of gold to interact with the bromine atom of silane 1 followed by inner-sphere electron transfer [27]. The radical then attacks silyl enol ether 2, and the subsequent silyloxy-substituted radical is oxidized by the photocatalyst to generate the

Photophysics and photochemistry of NIR absorbers derived from cyanines: key to new technologies based on chemistry 4.0

• Bernd Strehmel,
• Christian Schmitz,
• Ceren Kütahya,
• Yulian Pang,
• Anke Drewitz and
• Heinz Mustroph

Beilstein J. Org. Chem. 2020, 16, 415–444, doi:10.3762/bjoc.16.40

• the outer sphere coordinates (λo) while geometric changes of the starting materials responsible tune inner-sphere coordinates λi (λ = λo + λi) [72]. Many NIR sensitive systems possess an internal activation barrier although ΔGet < 0 using either the positively charged iodonium compound 88 (Ered

Recent advances in transition-metal-catalyzed incorporation of fluorine-containing groups

• Xiaowei Li,
• Xiaolin Shi,
• Xiangqian Li and
• Dayong Shi

Beilstein J. Org. Chem. 2019, 15, 2213–2270, doi:10.3762/bjoc.15.218

• , promoting the C–F over C–O bond formation via an inner-sphere pathway. Fluorination of arenes, aryl bromides, -alcohols, -triflates, and -boronic acid derivatives: In 2013, Larhed and co-workers [51] established a one-pot, two-step fluorination of aryl alcohols via aryl nonafluorobutylsulfonates. This

Cp₂TiCl/D₂O/Mn, a formidable reagent for the deuteration of organic compounds

• Antonio Rosales and
• Ignacio Rodríguez-García

Beilstein J. Org. Chem. 2016, 12, 1585–1589, doi:10.3762/bjoc.12.154

• water. This complex is a single electron transfer system (SET) that has an unpaired d-electron and a vacant site, allowing heteroatoms with free valence electrons to coordinate and undergo electron transfer through an inner-sphere mechanism to generate carbon radicals or intermediate titanaoxiranes

Evidencing an inner-sphere mechanism for NHC-Au(I)-catalyzed carbene-transfer reactions from ethyl diazoacetate

• Manuel R. Fructos,
• Juan Urbano,
• M. Mar Díaz-Requejo and
• Pedro J. Pérez

Beilstein J. Org. Chem. 2015, 11, 2254–2260, doi:10.3762/bjoc.11.245

• CHCO2Et to the substrate (styrene or methanol) takes place in the coordination sphere of Au(I) by means of an inner-sphere mechanism, in contrast to the generally accepted proposal of outer-sphere mechanisms for Au(I)-catalyzed reactions. Keywords: carbene transfer; inner sphere; gold catalysis; O–H

• homocoupling [15][16]. In this contribution we report the results obtained from a kinetic study carried out with the IPrAuCl complex that allows proposing a plausible inner-sphere mechanism in which the substrate (styrene or methanol) seems to remain coordinated to the gold center, a feature that could be

• has been proposed to be associative in most cases, the reaction then being triggered from there, usually through an outer-sphere mechanism. To the best of our knowledge, there are no evidences which support the alternative route, the inner-sphere mechanism. The kinetic data available from the previous

Influence of bulky yet flexible N-heterocyclic carbene ligands in gold catalysis

• Alba Collado,
• Scott R. Patrick,
• Danila Gasperini,
• Sebastien Meiries and
• Steven P. Nolan

Beilstein J. Org. Chem. 2015, 11, 1809–1814, doi:10.3762/bjoc.11.196

• ligands [46][50]. Each 19F{1H} NMR spectrum contains a singlet at ca. −76 ppm, in agreement with the presence of an inner-sphere NTf2 ligand [50]. Catalytic transformations Once fully characterised, the catalytic activity of the new complexes was investigated. To this end, three model reactions were

Anion effect controlling the selectivity in the zinc-catalysed copolymerisation of CO₂ and cyclohexene oxide

• Sait Elmas,
• Muhammad Afzal Subhani,
• Walter Leitner and
• Thomas E. Müller

Beilstein J. Org. Chem. 2015, 11, 42–49, doi:10.3762/bjoc.11.7

• react with a coordinated epoxide molecule, while protonation terminates the growth of this particular chain. In such an inner-sphere mechanism the epoxide molecules compete with the anion in coordination to the zinc centres. In particular, coordination of the epoxide to a zinc centre neighbouring a zinc

• ). Proposed inner-sphere mechanism for the copolymerisation of CO2 and CHO with binuclear zinc complexes (1: X = CF3SO3, 2: X = p-TSO3). Position and assignment of the NMR signals of complexes 1 and 2 in comparison to the parent macrocyclic ligand H2L. Yield and selectivity in the copolymerisation of CO2 and

Recent advances in the electrochemical construction of heterocycles

• Robert Francke

Beilstein J. Org. Chem. 2014, 10, 2858–2873, doi:10.3762/bjoc.10.303

• . In contrast, the indirect process can either be initiated with a discrete electron transfer (outer-sphere mechanism) or proceed via bond formation (inner-sphere mechanism), depending on the type of mediator [31]. In both cases, the electrode reaction proceeds at such a low potential that the

Copper(II)-salt-promoted oxidative ring-opening reactions of bicyclic cyclopropanol derivatives via radical pathways

• Eietsu Hasegawa,
• Minami Tateyama,
• Ryosuke Nagumo,
• Eiji Tayama and
• Hajime Iwamoto

Beilstein J. Org. Chem. 2013, 9, 1397–1406, doi:10.3762/bjoc.9.156

• initially to produce Lewis base–acid complex 7, followed by inner-sphere ET involving elimination of CuOAc and AcOH, which gives cyclopropoxy radical 8. Either external or internal bond cleavage of 8 generates the respective primary alkyl radical 9 or tertiary alkyl radical 10. An equilibrium