Cellulose as recyclable organocatalyst for ipso-hydroxylation of arylboronic acids

Synthesis of aryloxyacetamides from arylboronic acids and 2-bromoacetonitrile promoted by alkaline solutions of hydrogen peroxide

A novel and metal catalyst-free synthesis of aryloxyacetamides from the corresponding arylboronic acids and 2-bromoacetonitrile promoted by alkaline solutions of hydrogen peroxide has been developed involving an oxidation-reduction of eco-friendly H₂O₂ with simultaneous reaction ipso-hydroxylation of arylboronic acid and hydration of the nitrile. This protocol is compatible with sensitive substituents attached to the arylboronic acid and provides desired products in moderate to good yields in pure water.

Highly recyclable Ti0.97Ni0.03O1.97 catalyst coated on cordierite monolith for efficient transformation of arylboronic acids to phenols and reduction of 4-nitrophenol

A stable Ni²⁺ substituted TiO₂ catalyst (Ti_0.97Ni_0.03O_1.97) has been synthesized by a solution combustion method with an average crystallite size of 7.5 nm. Ti_1-xNi_xO_2-x (x = 0.01-0.06) crystallizes in the TiO₂ anatase structure with Ni²⁺ substituted in Ti⁴⁺ ion sites and Ni taking a nearly square planar geometry. This catalyst is found to be highly active in the transformation of diverse arylboronic acids to the corresponding phenols. The catalyst coated cordierite monolith can even be recycled for up to 20 cycles with a cumulative TOF of 1.8 × 10⁵ h^-1. In scale-up reactions, various phenols are synthesized by employing a single cordierite monolith. It also shows high performance in the reduction of 4-nitrophenol.

TYLENOL® and ASPIRIN® as green promoters for ipso-hydroxylation of arylboronic acids

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We explored the most expedient pathway for phenolic compound preparation using a combination of arylboronic acids, a green oxidant (H2O2) and a catalytic amount of readily available medicinal materials (TYLENOL® and ASPIRIN®). The ayrlboronic acids were successfully transformed into the corresponding phenols in high yields under metal- and base-free aqueous aerobic conditions. We demonstrated that enhanced availability and sustainability are some advantages associated with the use of medicinal supports.

Transition-Metal-Free Borylation of Aryl Bromide Using a Simple Diboron Source

In this study, we developed a simple transition-metal-free borylation reaction of aryl bromides. Bis-boronic acid (BBA), was used, and the borylation reaction was performed using a simple procedure at a mild temperature. Under mild conditions, aryl bromides were converted to arylboronic acids directly without any deprotection steps and purified by conversion to trifluoroborate salts. The functional group tolerance was considerably high. The mechanism study suggested that this borylation reaction proceeds via a radical pathway.

Copper nanoparticles supported on highly nitrogen-rich covalent organic polymers as heterogeneous catalysts for the ipso-hydroxylation of phenyl boronic acid to phenol

Here, we report the synthesis of highly nitrogen-rich covalent organic polymers as a solid heterogeneous catalyst for the oxidation of phenylboronic acid under atmospheric conditions in an aqueous medium to achieve very good yields up to 99%.