Recent progress in the synthesis of pyridinylboronic acids and esters

Liu, Yuxin; Milo, Lawrence J.; Lai, Jack H.

doi:10.3998/ark.5550190.0014.104

Cited by 8 publications

(4 citation statements)

References 61 publications

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“…The conversion of B 2 pin 2 paralleled the conversion of 4-picoline, which suggests that C–H borylation is leading to the formation of the multiple aromatic products. At this time we do not speculate on the mechanism of decomposition of the proposed 2-borylpyridyl products or the catalyst, but the instability of 2-borylpyridine derivatives is well documented. − …”

Section: Results and Discussionmentioning

confidence: 97%

Iridium-Catalyzed C–H Borylation of Heteroarenes: Scope, Regioselectivity, Application to Late-Stage Functionalization, and Mechanism

2014

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A study on the iridium-catalyzed C-H borylation of heteroarenes is reported. Several heteroarenes containing multiple heteroatoms were found to be amenable to C-H borylation catalyzed by the combination of an iridium(I) precursor and tetramethylphenanthroline. The investigations of the scope of the reaction led to the development of powerful rules for predicting the regioselectivity of borylation, foremost of which is that borylation occurs distal to nitrogen atoms. One-pot functionalizations are reported of the heteroaryl boronate esters formed in situ, demonstrating the usefulness of the reported methodology for the synthesis of complex heteroaryl structures. Application of this methodology to the synthesis and late-stage functionalization of biologically active compounds is also demonstrated. Mechanistic studies show that basic heteroarenes can bind to the catalyst and alter the resting state from the olefin-bound complex observed during arene borylation to a species containing a bound heteroarene, leading to catalyst deactivation. Studies on the origins of the observed regioselectivity show that borylation occurs distal to N-H bonds due to rapid N-H borylation, creating an unfavorable steric environment for borylation adjacent to these bonds. Computational studies and mechanistic studies show that the lack of observable borylation of C-H bonds adjacent to basic nitrogen is not the result of coordination to a bulky Lewis acid prior to C-H activation, but the combination of a higher-energy pathway for the borylation of these bonds relative to other C-H bonds and the instability of the products formed from borylation adjacent to basic nitrogen.

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Section: Results and Discussionmentioning

confidence: 97%

Iridium-Catalyzed C–H Borylation of Heteroarenes: Scope, Regioselectivity, Application to Late-Stage Functionalization, and Mechanism

2014

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“…Nevertheless, new synthetic strategies, based on recent developments in organic synthesis, still need to be explored due to, in particular, all increasing use of pyridine derivatives as ligands . 2-Halopyridines are important building blocks for synthesis of both pyridine derivatives and diverse pyridine-containing heterocycles via cross-coupling reactions. , Preparation of 2-halopyridines by direct halogenation of substituted pyridines suffers from poor regioselectivity and low reactivity of the pyridine core . Halogenation of pyridine N -oxides with phosgene, POX 3 , SOX 2 , and other halogenating agents is used more successfully; however, the problem of selectivity and using harsh reaction conditions are often characteristic of this approach too .…”

Section: Introductionmentioning

confidence: 99%

Fe(II)/Au(I) Relay Catalyzed Propargylisoxazole to Pyridine Isomerization: Access to 6-Halonicotinates

et al. 2017

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“…There is no doubt that elucidating these terms is likely to help chemists to design the reactions of the higher‐order MCRs. Tandem reaction is viewed as reactions that occur in a sequential fashion [68] . In addition, a cascade reaction may encompass an MCR and is categorized as such when the simultaneous addition of all substrates, catalysts, ligands and additives at the onset of the reaction is feasible, with reactants then combining in a uniquely ordered manner under the same reaction conditions [69] .…”

Section: Mcr: Principles Terms and Designmentioning

confidence: 99%

Six‐Component Reactions and Beyond: The Nuts and Bolts

Hooshmand

Yazdani²,

Hulme

2022

Eur J Org Chem

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The deployment of multicomponent reactions (MCRs), defined as containing three or more reactants, not only enjoys pot, atom, and step‐economy in the synthesis of novel complex molecules but also aligns with sustainable chemistry principles as a green symphony. Generally, more components lead to more complexity, and are taken to an extreme ‘‘higher‐order’’ MCRs, where six or even more components react in a one‐pot, have been developed, although they remain scarce compared to their 3, 4 and 5‐component relatives. On this topic, the rich footprint of isocyanides in MCRs has been fruitful in delivering higher order six to eight‐component reactions through mechanistically similar pathways. The present review encompasses a brief history of MCRs and their product utility, followed by a thorough discussion of the principles of reaction design that enabled the discovery of higher‐order MCRs, spanning 6 to 8‐components. Future challenges and opportunities will also be elaborated.

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Recent progress in the synthesis of pyridinylboronic acids and esters

Cited by 8 publications

References 61 publications

Iridium-Catalyzed C–H Borylation of Heteroarenes: Scope, Regioselectivity, Application to Late-Stage Functionalization, and Mechanism

Iridium-Catalyzed C–H Borylation of Heteroarenes: Scope, Regioselectivity, Application to Late-Stage Functionalization, and Mechanism

Fe(II)/Au(I) Relay Catalyzed Propargylisoxazole to Pyridine Isomerization: Access to 6-Halonicotinates

Six‐Component Reactions and Beyond: The Nuts and Bolts

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