Rapid synthesis of alkylaminophenols via the Petasis borono–Mannich reaction using protonated trititanate nanotubes as robust solid–acid catalysts

Reddy, Bhoomireddy Rajendra Prasad; Reddy, Peddiahgari Vasu Govardhana; Kumar, D. Praveen; Reddy, Bijivemula N.; Shankar, M.V.

doi:10.1039/c5ra25064a

Cited by 30 publications

(9 citation statements)

References 93 publications

(3 reference statements)

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“…The methodology could also be extended to a series of piperazine-substituted aminophenols. 43,77 Other catalysts, including lanthanum(III) trifluoromethanesulfonate, Mg–Al mixed oxides, and 4 Å supported copper catalysts, were also applied in the PR of salicylaldehyde, morpholine, and arylboronic acid. 88,89 2-(Aryl(piperidin-1-yl)methyl)phenols sharing the same or higher structural familiarity as 28 were recently used as substrates for the synthesis of 9-aryl-2,3,4,9-tetrahydro-1 H -xanthen-1-ones in a FeCl 3 -mediated approach involving nucleophilic substitution and intramolecular cyclization steps.…”

Section: Three-component Petasis Reactionsmentioning

confidence: 99%

Reactivity and Synthetic Applications of Multicomponent Petasis Reactions

2019

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The Petasis boron–Mannich reaction, simply referred to as the Petasis reaction, is a powerful multicomponent coupling reaction of a boronic acid, an amine, and a carbonyl derivative. Highly functionalized amines with multiple stereogenic centers can be efficiently accessed via the Petasis reaction with high levels of both diastereoselectivity and enantioselectivity. By drawing attention to examples reported in the past 8 years, this Review demonstrates the breadth of the reactivity and synthetic applications of Petasis reactions in several frontiers: the expansion of the substrate scope in the classic three-component process; nonclassic Petasis reactions with additional components; Petasis-type reactions with noncanonical substrates, mechanism, and products; new asymmetric versions assisted by chiral catalysts; combinations with a secondary or tertiary transformation in a cascade- or sequence-specific manner to access structurally complex, natural-product-like heterocycles; and the synthesis of polyhydroxy alkaloids and biologically interesting molecules.

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Section: Three-component Petasis Reactionsmentioning

confidence: 99%

Reactivity and Synthetic Applications of Multicomponent Petasis Reactions

2019

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“…The inducing of Brønsted acidity in the protonated titanate nanotubes is explained by some of the structural factors [37]. In line with the works of [36,[38][39][40], the acid sites in the H + -exchanged titanate nanotube were generated by the hydroxyl groups on the scrolled titanate nanosheets. Although the acid strength of H + -exchanged titanate is weak, the hydroxyl groups pointing towards the center of the nanotube may lead to a strong electric field that behaves as a strong acid site.…”

Section: Acidity By Py-irmentioning

confidence: 63%

Hydrodesulfurization of 4,6-Dimethyldibenzothiophene and the Diesel Oil Fraction on NiMo Catalysts Supported over Proton-Exchanged AlMCM-41 and TiMCM-41 Extrudates

et al. 2021

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NiMo catalysts supported on mesoporous MCM-41 type materials shaped with binder were tested for activity in the hydrodesulfurization of 4,6-dimethyldibenzothiophene (4,6-DMDBT) and the diesel fuel fraction (0.92 wt% of sulfur). The aim of the investigation was to evaluate the effect of ion exchange with protons of Al- or Ti-substituted MCM-41 mesoporous supports. The subjected catalytic systems were NiMo/HAlMCM-41 and NiMo/HTiMCM-41, and for comparison purposes NiMo/AlMCM-41 and NiMo/TiMCM-41. The samples were characterized by N2 sorption (at 77 K), XRD, TEM, XPS, SEM and Py–IR. It was found that the functionalization of AlMCM-41 and TiMCM-41 with protons increased the conversion of 4,6-DMDBT and the pseudo-first-order rate constant. Correspondingly, 4,6-DMDBT HDS reactions over the NiMo/HTiMCM-41 catalyst proceeded to a similar extent via hydrogenation and direct desulfurization, whereas over the NiMo/HAlMCM-41 they proceeded mainly via direct desulfurization. Furthermore, the ion-exchanged catalysts displayed two-fold higher efficiency in direct desulfurization than their non-modified counterparts. The NiMo/HTiMCM-41 catalyst exhibited the highest catalytic efficiency in the HDS of 4,6-DMDBT and the diesel oil fraction. The high activity of the NiMo/HTiMCM-41 catalyst is mainly attributed to its appropriate acidity, as well as the metal–support interaction providing both the high dispersion of the active phase and the desirable multilayered stacking morphology of the active phase slabs.

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“…Also, boronic acids, esters, and even trifluoroborates have been used in this transformation, showing its extensive scope. Furthermore, many highly efficient asymmetric organocatalytic procedures, as well as new and diverse technologies, have been developed in recent years …”

Section: Introductionmentioning

confidence: 99%

Theoretical Study of the Borono–Mannich Reaction with Pinacol Allenylboronate

Pellegrinet

2020

J. Org. Chem.

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A density functional theory study of the mechanism of the Borono–Mannich reaction using benzylamine and piperidine as representative examples of primary and secondary amines with pinacol allenylboronate is presented. The study shows that both reactions progress through coordination between the boron and the phenolic oxygen. Ring size strain and hydrogen bond activation appear to determine the observed divergent regioselectivity. In the case of benzylamine, the eight-membered ring transition structure that leads to the propargylamine exhibits a hydrogen bond between the hydrogen attached to the nitrogen and the phenolic oxygen (γ-attack), whereas for piperidine a hydrogen bond between the hydrogen on the imine carbon and one of the oxygens of the pinacol group was observed in the six-membered ring transition structure toward the allenylamine (α-attack).

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Rapid synthesis of alkylaminophenols via the Petasis borono–Mannich reaction using protonated trititanate nanotubes as robust solid–acid catalysts

Abstract: The Petasis borono–Mannich reaction was applied to the synthesis of alkylaminophenols from o-hydroxybenzaldehydes, secondary amines and boronic acids in the presence of H2Ti3O7 nanotubes as reusable solid–acid catalysts.

Cited by 30 publications

References 93 publications

Reactivity and Synthetic Applications of Multicomponent Petasis Reactions

Reactivity and Synthetic Applications of Multicomponent Petasis Reactions

Hydrodesulfurization of 4,6-Dimethyldibenzothiophene and the Diesel Oil Fraction on NiMo Catalysts Supported over Proton-Exchanged AlMCM-41 and TiMCM-41 Extrudates

Theoretical Study of the Borono–Mannich Reaction with Pinacol Allenylboronate

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