Ipso-Hydroxylation of Aryl/Heteroarylboronic Acids Using EBPA as a Green Catalyst

作者：Saikia Eramoni; Chetia Bolin; Bora Sankar Jyoti

来源：Letters in Organic Chemistry, 2016, 13(10): 764-769.

DOI：10.1174/1570178614666161119114840

• Catalysis
• homogeneous
• WEBPA
• boronic acid
• ipso-hydroxylation
• phenols

Background: As the phenols and its derivatives are considered as versatile precursors, herbicides, drugs and antioxidants, the synthesis of phenols has been gaining much attention during the last decades. Despite the numerous methods for phenol synthesis there is a serious need for "green" protocols with greater environmental benign and economic viability.
Method: We used a highly abundant and inexpensive natural feedstock WEBPA (Water Extract of Banana Peel Ashes) with 30% aqueous H2O2 as an oxidant for the synthesis of phenol and its derivatives.
Results: Ipso -hydroxylation of twelve different types aryl and hetero aryl boronic acids with both electron donating and electron withdrawing groups such as OMe, Me, Cl, NO2, COMe etc. has been carried out by the newly developed protocol with excellent yields in a short period of time. The catalytic system has also been found effective up to 5th cycle without significant loss of activity.
Conclusion: In conclusion, we have developed a reusable, mild, and efficient protocol for the ipso hydroxylation of aryl/heteroarylboronic acids. This protocol seems to be one of the greenest and economic alternatives to the existing protocol.

• 出版日期2016