In recent years, organic reactions in water have received considerable attention Citation17–20. However, these conditions are not chemoselective, require harsh conditions, long reaction time, and nucleophilic organocatalysts used sometimes involve the generation of side products in significant quantities such as symmetrical carbonates, cyclic carbonates, and carbonic–carbonic anhydrides Citation8. Citation16 described a new method for the protection/deprotection of the O- tert-butoxy carbonates of alcohols and phenols using mesoporous silica-supported (Er III-MCM-41). Citation15 reported the O- tert-butoxycarbonylation of functionalized phenols using carbon tetrabromide (CBr 4) as catalyst and their regeneration from the O- tert-Boc derivatives using the complex system CBr 4–PPh 3. In spite of their importance, there are a few methods available for the protection/deprotection of O-Boc groups under eco-sustainable conditions. On the other hand, the O-Boc deprotection is carried out under mild acidic conditions such as trifluoroacetic acid (TFA) Citation13 and the use of a large excess of base Citation14. The introduction of Boc moiety into phenols is generally achieved by the reaction of (Boc) 2O in the presence of a phase transfer catalyst Citation7, 4-dimethylaminopyridine (DMAP) as catalyst Citation8 and using Lewis acids such as BiCl 3 Citation9, Zn(OAc) 2 Citation10, 1- tert-butoxy-2- tert-butoxycarbonyl-1,2-dihydroisoquinoline (BBDI) Citation3 Citation4 and NaTiO 4 Citation11, or using 6,7-dimethoxyisoquinoline Citation12 as an organocatalyst. In the last decade, various methods and reagents have been developed to achieve the protection/deprotection of Boc group on phenol functionality. Furthermore, O-tert-butoxycarbonylation is a suitable and preferred alternative process to protect hydroxyl group Citation1 Citation2 due to both sustainable compatibility toward reaction conditions applied in organic synthesis and regeneration practices conducted under soft conditions. 10.1080/17518253.2012.738371-SUP0001 A simple and eco-sustainable method for the O-Boc formation/cleavage of various phenolic structures under water-mediated/catalyst-free conditionsĪcylation is a common approach in protecting hydroxyl groups Citation5 Citation6, but its regeneration requires harsh conditions incompatible with polyfunctional molecules. ![]() The insertion of Boc group is usually achieved using di- tert-butyl dicarbonate (Boc) 2O, being the best available reagent used for protecting substrates containing a labile-hydrogen moiety such as phenol-type Citation3 Citation4. Tert-butyl carbamates are widely used as amine-protecting groups in various fields of organic synthesis due to its stability toward nucleophilic conditions and due to its easy removal in various environments. ![]() Efforts have been made to identify mild and efficient chemoselective methods for the protection/deprotection of functional groups, crucial interest to organic multi-step synthesis Citation1 Citation2.
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