Site-Selective and Stereoselective C(sp3)–H Borylation of Alkyl Side Chains of 1,3-Azoles with a Silica-Supported Monophosphine-Iridium Catalyst

Murakami, Ryo; Iwai, Tomohiro; Sawamura, Masaya

doi:10.1055/s-0035-1561599

Cited by 17 publications

(2 citation statements)

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“…Moreover, both secondary and tertiary C-H bonds were amenable towards the borylation reaction showcasing the versatility of the catalytic system. Sawamura and co-workers were able to demonstrate the utilization of the heterogeneous ligand system towards the site-selective and stereoselective C(sp 3 )-H borylation (Murakami et al, 2016) of the alkyl side chains of 1,3-azoles under mild reaction conditions (2 mol% Ir, 50-90 °C), giving both primary and secondary alkylboronate derivatives (Figure 46). The reaction tolerates a variety of 1,3-(benzo)azoles including thiazoles, oxazoles, and imidazoles.…”

Section: Figure 36 Silyl-directed Ortho-borylation Of Arenesmentioning

confidence: 99%

An Introductory Overview of C–H Bond Activation/ Functionalization Chemistry with Focus on Catalytic C(sp3)–H Bond Borylation

Reyes

Sawamura

2021

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The direct and selective functionalization of C–H bonds provides novel disconnections and innovative strategies to streamline the synthesis of molecules with diverse complexities. However, despite the significant advances in the elaboration of techniques for C–H activation, the utilization of unactivated C(sp3)–H bonds remains challenging. In particular, asymmetric transformation of C(sp3)–H bonds is underdeveloped owing to the lack of catalytic systems that can competently discriminate among ubiquitous C–H bonds in organic molecules. This short review aims to outline the challenges and strategies for the catalytic functionalization of C(sp3)–H bonds giving a general and non-exhaustive explanatory approach. Current strategies on the basis of the substrates and reaction mechanisms are summarized in Section 1. Examples of enantioselective C–H bond transformations are then given in Section 2. Finally, in Section 3, an outline of current methodologies towards the direct borylation of C(sp3)–H bonds is described to showcase the importance of developing techniques for catalytic C–H bond chemistry. While we try to cover all excellent reports available in the literature on this topic, any omissions are unintentional, taking note of the most representative examples available.

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Section: Figure 36 Silyl-directed Ortho-borylation Of Arenesmentioning

confidence: 99%

An Introductory Overview of C–H Bond Activation/ Functionalization Chemistry with Focus on Catalytic C(sp3)–H Bond Borylation

Reyes

Sawamura

2021

KIMIKA

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“…While transition-metal (TM) catalyzed Csp 2 À H borylation methodologies are widespread, the catalytic borylation of Csp 3 À H substrates are uniquely challenging because of the sterically demanding geometry of Csp 3 À H compared to planar Csp 2 À H and the absence of easily accessible frontier molecular orbitals for coordination with the catalysts. [25] TM catalyzed methodologies for the CÀ H functionalization of cyclic amine frameworks have been developed using directing groups, [26][27][28][29][30][31][32][33] such as pyridine as pioneered by the Sawamura group using Rh [28] and Ir [29] complexes (Figure 1a).…”

Section: Introductionmentioning

confidence: 99%

Metal‐Free Directed Site‐Selective Csp³‐H Borylation of Saturated Cyclic Amines

et al. 2023

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The borylation of Csp3‐H bonds is a challenging transformation that is typically restricted to transition metal catalysis. Herein, we report the site‐selective metal‐free Csp3–H borylation of saturated cyclic amines. It is possible to selectively borylate piperidine derivatives at the α or β positions according to the reaction conditions. The mechanism was supported by NMR spectroscopy, calorimetry experiments and density functional theory (DFT) computations. It suggests that the piperidine is dehydrogenated by complexation with BBr3 to produce an enamine intermediate, which is in turn borylated at either the α or β position according to the reaction conditions.

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A General and Practical Approach for the Synthesis of 1,2,4‐Trioxanes Catalyzed by Silica‐Ferric Chloride

et al. 2017

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An efficient andp ractical method has been developed for the facile synthesiso f1 ,2,4-trioxanes by the condensation of b-hydroperoxy alcohols and carbonylcompoundsinthe presence of acatalytic amount of silica-supported ferric chloride (FeCl 3 / SiO 2 )a tr oom temperature.T he method has the benefits of operational simplicity, high yieldsa nd potential large-scale application. Moreover, the catalyst can be readily recovered by simple filtration and reused up to five times while almost maintaining its catalytic activity.

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Site-Selective and Stereoselective C(sp3)–H Borylation of Alkyl Side Chains of 1,3-Azoles with a Silica-Supported Monophosphine-Iridium Catalyst

Cited by 17 publications

References 8 publications

An Introductory Overview of C–H Bond Activation/ Functionalization Chemistry with Focus on Catalytic C(sp3)–H Bond Borylation

An Introductory Overview of C–H Bond Activation/ Functionalization Chemistry with Focus on Catalytic C(sp3)–H Bond Borylation

Metal‐Free Directed Site‐Selective Csp³‐H Borylation of Saturated Cyclic Amines

A General and Practical Approach for the Synthesis of 1,2,4‐Trioxanes Catalyzed by Silica‐Ferric Chloride

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Site-Selective and Stereoselective C(sp3)–H Borylation of Alkyl Side Chains of 1,3-Azoles with a Silica-Supported Monophosphine-Iridium Catalyst

Cited by 17 publications

References 8 publications

An Introductory Overview of C–H Bond Activation/ Functionalization Chemistry with Focus on Catalytic C(sp3)–H Bond Borylation

An Introductory Overview of C–H Bond Activation/ Functionalization Chemistry with Focus on Catalytic C(sp3)–H Bond Borylation

Metal‐Free Directed Site‐Selective Csp3‐H Borylation of Saturated Cyclic Amines

A General and Practical Approach for the Synthesis of 1,2,4‐Trioxanes Catalyzed by Silica‐Ferric Chloride

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Metal‐Free Directed Site‐Selective Csp³‐H Borylation of Saturated Cyclic Amines