Iridium-Catalyzed Asymmetric Allylic Substitution Reactions

Chemical Reviews, Journal Year: 2018, Volume and Issue: 119(3), P. 1855 - 1969

Published: Dec. 24, 2018

In this review, we summarize the origin and advancements of iridium-catalyzed asymmetric allylic substitution reactions during past two decades. Since first report in 1997, Ir-catalyzed have attracted intense attention due to their exceptionally high regio- enantioselectivities. been significantly developed recent years many respects, including ligand development, mechanistic understanding, substrate scope, application synthesis complex functional molecules. an explicit outline ligands, mechanism, scope nucleophiles, applications is presented.

Language: Английский

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

Advanced Synthesis & Catalysis, Journal Year: 2021, Volume and Issue: 363(13), P. 3146 - 3169

Published: April 10, 2021

Abstract Chemists are generally familiar with polar reactions and radical reactions, in comparison, underdeveloped. In the last few years, however, novel concept of amalgamation above two form radical‐polar crossover (RPCO) polar‐radical (PRCO) has emerged as a valuable powerful tool. This methodology tends to bridge gap between well overcomes limitations both traditional chemistry. By bringing together unorthodox chemistry radicals orthodox carbocations carbanions, green quotient such is significantly improved. The development shaping up this area years synthetically important transformations summarised review. magnified image

Language: Английский

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Electrochemical Enantioselective Nucleophilic α-C(sp³)–H Alkenylation of 2-Acyl Imidazoles

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(15), P. 6964 - 6971

Published: April 6, 2022

Merging electrochemistry with asymmetric catalysis promises to provide an environmentally friendly and efficient strategy for the construction of nonracemic chiral molecules. However, in practice, significant challenges arise from instability or incompatibility catalysts under electrochemical conditions at interface electrode solution. Herein, we report a catalytic indirect electrolysis employing combination redox mediator chiral-at-rhodium Lewis acid, which achieves previously elusive enantioselective nucleophilic α-C(sp3)−H alkenylation ketones. Specifically, 2-acyl imidazoles react potassium alkenyl trifluoroborates high yields (up 94%) exceptional enantioselectivities (27 examples ≥99% ee) without need any additional stoichiometric oxidants (overall 40 examples). The new electrosynthesis can be scaled gram quantities was applied straightforward synthesis intermediates natural product cryptophycin A cathepsin K inhibitor.

Language: Английский

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S-adenosylhomocysteine as a methyl transfer catalyst in biocatalytic methylation reactions

Nature Catalysis, Journal Year: 2019, Volume and Issue: 2(8), P. 696 - 701

Published: June 17, 2019

Language: Английский

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Photochemical Asymmetric Nickel‐Catalyzed Acyl Cross‐Coupling

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 58(47), P. 16854 - 16858

Published: Sept. 18, 2019

Abstract Photochemical enantioselective nickel‐catalyzed cross‐coupling reactions are difficult to implement. We report a visible‐light‐mediated strategy that successfully couples symmetrical anhydrides and 4‐alkyl dihydropyridines (DHPs) afford enantioenriched α‐substituted ketones under mild conditions. The chemistry does not require exogenous photocatalysts. It is triggered by the direct excitation of DHPs, which act as radical source reductant, facilitating turnover chiral catalytic nickel complex.

Language: Английский

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Methylene C(sp³)–H Arylation of Aliphatic Ketones Using a Transient Directing Group

ACS Catalysis, Journal Year: 2017, Volume and Issue: 7(10), P. 6938 - 6941

Published: Sept. 13, 2017

Palladium-catalyzed methylene β-C(sp

Language: Английский

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A Photochemical Organocatalytic Strategy for the α‐Alkylation of Ketones by using Radicals

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(24), P. 9485 - 9490

Published: Feb. 13, 2020

Abstract Reported herein is a visible‐light‐mediated radical approach to the α‐alkylation of ketones. This method exploits ability nucleophilic organocatalyst generate radicals upon S N 2‐based activation alkyl halides and blue light irradiation. The resulting open‐shell intermediates are then intercepted by weakly silyl enol ethers, which would be unable directly attack through traditional two‐electron path. mild reaction conditions allowed functionalization α position ketones with functional groups that not compatible classical anionic strategies. In addition, redox‐neutral nature this process makes it cinchona‐based primary amine catalyst, was used develop rare example enantioselective organocatalytic

Language: Английский

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Organolithium Bases in Flow Chemistry: A Review

Organic Process Research & Development, Journal Year: 2020, Volume and Issue: 24(10), P. 1814 - 1838

Published: April 30, 2020

Flow chemistry is a continually emerging and ever-growing area of synthetic organic chemistry. It provides an orthogonal approach to traditional batch chemistry, oftentimes allowing for more efficient routes desired target molecules. generally accepted that flow offers valuable change the process landscape. From perspective, there are many advantages associated with over most prominent which increased safety profile use highly reactive chemical species, such as organolithiums. These reagents species synthesis pharmaceutical intermediates. Disadvantageously, these on commercial scale severely hindered by energetic nature reaction intermediates their concomitant risk. viable platform reagents, offering high degree control parameters. In this review, we present comprehensive account published literature implementing organolithium strong bases deprotonation reactions in systems.

Language: Английский

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Dancing on Ropes ‐ Enantioselective Functionalization of Preformed Four‐Membered Carbocycles

Chinese Journal of Chemistry, Journal Year: 2022, Volume and Issue: 40(11), P. 1346 - 1358

Published: Feb. 12, 2022

Comprehensive Summary Cyclobutane derivatives have been recognized as useful structural motifs in organic synthesis and drug design. With the revival of photochemistry, enantioselective cyclobutane using [2 + 2]‐cycloadditions has garnered numerous attentions. On other hand, functionalization preformed four‐membered carbocycles is emerging an important complementary approach to access chiral with versatile patterns. Herein, we summarize recent advances this field from 2012. To avoid undesired C—C bond cleavage driven by strain‐releasing, it crucial choose compatible methods for meanwhile preserving intact ring skeleton. Guided calculated hydrogenation enthalpies, which are used evaluate strain energy indicated bond, a clear picture developed methodologies on combining enhanced reactivity presented.

Language: Английский

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Catalytic Photochemical Deracemization via Short‐Lived Intermediates

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(50)

Published: July 10, 2023

Upon irradiation in the presence of a suitable chiral catalyst, racemic compound mixtures can be converted into enantiomerically pure compounds with same constitution. The process is called photochemical deracemization and involves formation short-lived intermediates. By opening different reaction channels for forward to intermediate re-constitution molecule, entropically disfavored becomes feasible. Since discovery first 2018, field has been growing rapidly. This review comprehensively covers research performed area discusses current developments. It subdivided according mode action respective substrate classes. focus this on scope individual reactions discussion mechanistic details underlying presented reaction.

Language: Английский

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