Carbocatalysis: reduced graphene oxide-catalyzed Boc protection of hydroxyls and graphite oxide-catalyzed deprotection

Xu, Yungen; Qi, Jun-Mei; Sun, Fangli; Ma, Ning

doi:10.1016/j.tetlet.2015.04.027

Cited by 11 publications

(7 citation statements)

References 50 publications

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“…1 H NMR (300 MHz, CDCl 3 ): δ 0.88 (t, J = 6.6 Hz, 3H, C8H, CH 3 ), 1.27–1.29 (m, 8H, CH 2 ), 1.51 (s, 9H, C2′H, −C(CH 3 ) 3 ), 1.58–1.71 (m, 4H, CH 2 ), 4.05 (t, J = 6.9, 2H, C1H, OCH 2 ). The 1 H NMR was consistent with that reported in the literature …”

Section: Methodssupporting

confidence: 89%

“…Similarly in the case of ethers, Sharma and Mahalingam demonstrated the application of Yb(OTf) 3 for the deprotection of prenyl ethers to alcohols at room temperature in nitromethane (CH 3 NO 2 ), whereas the conversion of alcohols into p -methoxybenzyl ethers was reported in dichloromethane (DCM) at room temperature by Sharma and Mahalingam . These studies showed that the critical evaluation of time, solvent, and temperature might prove useful to identify the appropriate condition required for the formation of tert -butyl ethers from alcohols as in the case of Er(OTf) 3 . , …”

Section: Introductionmentioning

confidence: 80%

“… 15 These studies showed that the critical evaluation of time, solvent, and temperature might prove useful to identify the appropriate condition required for the formation of tert -butyl ethers from alcohols as in the case of Er(OTf) 3 . 6 , 16 …”

Section: Introductionmentioning

confidence: 99%

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Yb(OTf)₃-Catalyzed and Di-tert-butyl Dicarbonate-Mediated Decarboxylative Etherification and Esterification Reactions

et al. 2020

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Protecting group chemistry has invariably captured the fascination of chemists because of its extensive viability in chemical synthesis. The present report describes our pioneer work of applying ytterbium triflate as a catalyst, for the reaction of alcohols with di- tert -butyl dicarbonate (Boc 2 O) leading to the formation of tert -butyl ethers. There exists no recorded evidence for the use of Yb(OTf) 3 as a catalyst for the protection of alcohols to tert -butyl ethers, despite its excellent utility in various reactions. Yb(OTf) 3 has been used predominantly in the catalytic deprotection studies such as selective deprotection of tert -butyl esters to carboxylic acids as well as prenyl ethers to alcohols. This study involved the critical evaluation of solvent, time, and temperature that finally led to an efficient protocol for the formation of tert -butyl ethers. Yb(OTf) 3 catalyzed the formation of tert -butyl ethers, notably reducing the reaction time, which is exemplified by the achievement of up to 92% conversion of alcohols to tert -butyl ethers within an hour. Additionally, the report demonstrates the utility of this synthetic protocol for the protection of carboxylic acids.

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Section: Methodssupporting

confidence: 89%

Section: Introductionmentioning

confidence: 80%

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Yb(OTf)₃-Catalyzed and Di-tert-butyl Dicarbonate-Mediated Decarboxylative Etherification and Esterification Reactions

et al. 2020

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“…Graphene oxide (GO), a 2D, carbonaceous material bearing different oxygen functional groups such as alcohol, epoxide, ketones, and carboxylic acid 9–12 , is emerging as a green alternative for organic transformations and particularly superb in acidic carbocatalysis 5,13,14 . The inherent Brønsted acidity of GO, due to the presence of acidic oxygen groups on the edge of GO sheets, has been well exploited in the synthesis of benzylpyrazolyl coumarins 15 , thioacetals 16 , ethers 17 , and other Brønsted acid-catalyzed reactions such as transamidation 18 , Fisher esterification 19–22 , Boc-protection of alcohols 23 , and Kabachnik-Fields reactions 24 . Despite these extensive studies, only the Brønsted acidic nature of GO was recognized.…”

Section: Introductionmentioning

confidence: 99%

Regenerable Acidity of Graphene Oxide in Promoting Multicomponent Organic Synthesis

Ebajo

Santos

Alea

et al. 2019

Sci Rep

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The Brønsted acidity of graphene oxide (GO) materials has shown promising activity in organic synthesis. However, roles and functionality of Lewis acid sites remain elusive. Herein, we reported a carbocatalytic approach utilizing both Brønsted and Lewis acid sites in GOs as heterogeneous promoters in a series of multicomponent synthesis of triazoloquinazolinone compounds. The GOs possessing the highest degree of oxidation, also having the highest amounts of Lewis acid sites, enable optimal yields (up to 95%) under mild and non-toxic reaction conditions (85 °C in EtOH). The results of FT-IR spectroscopy, temperature-programed decomposition mass spectrometry, and X-ray photoelectron spectroscopy identified that the apparent Lewis acidity via basal plane epoxide ring opening, on top of the saturated Brønsted acidic carboxylic groups, is responsible for the enhanced carbocatalytic activities involving Knoevenagel condensation pathway. Recycled GO can be effectively regenerated to reach 97% activity of fresh GO, supporting the recognition of GO as pseudocatalyst in organic synthesis.

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“…Under these conditions, however, the Boc‐protected alcohols have been frequently accompanied by the corresponding undesired symmetrical carbonates as byproducts . There have been reports on improving the methods for preparing Boc‐protected alcohols in the presence of catalysts such as CeCl 3 , V(O)(OTf) 2 , Zn(OAc) 2 , BiCl 3 , NaLaTiO 4 , mesoporous silica‐supported Er(III), MgO‐ZrO 2 nanoparticles, o ‐Py 4 Sn, and reduced graphene oxide, as well as by a catalyst‐free microwave‐assisted approach . Although these methods are useful under limited conditions, the production of Boc protected alcohols is still dependent on the alcohol structures.…”

Section: Methodsmentioning

confidence: 99%

Lipase‐Catalyzed tert‐Butoxycarbonylation of Alcohols Using Boc₂O

Kishi

Kojima

2019

ChemistrySelect

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Lipase‐catalyzed tert‐butoxycarbonylation of alcohols using di‐tert‐butyl dicarbonate (Boc2O) was developed. Aspergillus niger lipase, Burkholderia cepacia lipase, Pseudomonas fluorescens lipase, Candida rugosa lipase, and Candida antarctica lipase B were examined. The reaction of benzyl alcohol with Boc2O proceeded smoothly in the presence of Candida rugosa lipase in hexane to produce benzyl tert‐butyl carbonate in a good yield. Similarly, the tert‐butoxycarbonylation reactions of 4‐methylbenzyl alcohol, 4‐methoxybenzyl alcohol, 4‐chlorobenzyl alcohol, 4‐bromobenzyl alcohol, 4‐nitrobenzyl alcohol, 2‐phenylethanol, 3‐phenyl‐1‐propanol, cinnamyl alcohol, and 2‐naphthalene methanol using Boc2O in the presence of Candida rugosa lipase in hexane resulted in very good to‐excellent yields of the corresponding tert‐butoxycarbonylated alcohols.

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Carbocatalysis: reduced graphene oxide-catalyzed Boc protection of hydroxyls and graphite oxide-catalyzed deprotection

Cited by 11 publications

References 50 publications

Yb(OTf)₃-Catalyzed and Di-tert-butyl Dicarbonate-Mediated Decarboxylative Etherification and Esterification Reactions

Yb(OTf)₃-Catalyzed and Di-tert-butyl Dicarbonate-Mediated Decarboxylative Etherification and Esterification Reactions

Regenerable Acidity of Graphene Oxide in Promoting Multicomponent Organic Synthesis

Lipase‐Catalyzed tert‐Butoxycarbonylation of Alcohols Using Boc₂O

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Carbocatalysis: reduced graphene oxide-catalyzed Boc protection of hydroxyls and graphite oxide-catalyzed deprotection

Cited by 11 publications

References 50 publications

Yb(OTf)3-Catalyzed and Di-tert-butyl Dicarbonate-Mediated Decarboxylative Etherification and Esterification Reactions

Yb(OTf)3-Catalyzed and Di-tert-butyl Dicarbonate-Mediated Decarboxylative Etherification and Esterification Reactions

Regenerable Acidity of Graphene Oxide in Promoting Multicomponent Organic Synthesis

Lipase‐Catalyzed tert‐Butoxycarbonylation of Alcohols Using Boc2O

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Product

Resources

About

Yb(OTf)₃-Catalyzed and Di-tert-butyl Dicarbonate-Mediated Decarboxylative Etherification and Esterification Reactions

Yb(OTf)₃-Catalyzed and Di-tert-butyl Dicarbonate-Mediated Decarboxylative Etherification and Esterification Reactions

Lipase‐Catalyzed tert‐Butoxycarbonylation of Alcohols Using Boc₂O