1. Biocatalysis of aromatic benzyl-propionate ester by different immobilized lipases
Amanda Gomes Almeida Sá, Alessandra Cristina de Meneses, Lindomar Alberto Lerin, Pedro Henrique Hermes de Araújo, Cláudia Sayer, Débora de Oliveira Bioprocess Biosyst Eng. 2018 May;41(5):585-591. doi: 10.1007/s00449-018-1893-4. Epub 2018 Jan 19.
Benzyl propionate is an aromatic ester that possesses a fruity odor and is usually found in nature in the composition of some fruits such as plums and melons. This work aimed for the benzyl propionate synthesis by esterification using a new immobilized enzyme preparation with low-cost material from Candida antarctica (NS 88011) and three commercial immobilized lipases (Novozym 435, Lipozyme TL-IM and Lipozyme RM-IM). Novozym 435 had the best performance even when the solvent tert-butanol was absent of the reaction medium. Results from a 22 factorial design showed that an increase in the enzyme amount led to a higher conversion, even when the temperature was kept at the low value. Currently, no research had synthesized successfully benzyl propionate via esterification mediated by lipases; and we reached an ester conversion of ~ 44% after 24 h indicating that it is a promising route for benzyl propionate biotechnological production.
3. Electrochemical Benzylic C(sp3)-H Acyloxylation
Alexander P Atkins, Albert C Rowett, David M Heard, Joseph A Tate, Alastair J J Lennox Org Lett. 2022 Jul 22;24(28):5105-5108. doi: 10.1021/acs.orglett.2c01930. Epub 2022 Jul 13.
The development of sustainable C(sp3)-H functionalization methods is of great interest to the pharmaceutical and agrochemical industries. Anodic oxidation is an efficient means of producing benzylic cations that can undergo subsequent in situ nucleophilic attack to afford functionalized benzylic products. Herein, we demonstrate the suitability of carboxylic acids as nucleophiles to yield benzylic esters. This method employs a series of secondary benzylic substrates and functionalized carboxylic acids and is demonstrated on a gram scale in flow.