Lipophilic Indole-Catalyzed Intermolecular Bromoesterification of Olefins in Nonpolar Media

Abstract

An environmentally benign and highly versatile catalytic protocol has been successfully applied in the intermolecular bromoesterification between various olefins and carboxylic acids. The use of a highly lipophilic indole catalyst and 1,3-dibromo-5,5-dimethylhydantoin (DBDMH) as the bromine source allows the reaction to proceed in heptane via a solid–liquid phase transfer mechanism, affording the corresponding bromoester products in good-to-excellent yields.

Amphiphilic Indoles as Efficient Phase‐Transfer Catalysts for Bromination in Water

“…Recently, we introduced lipophilic indoles (e. g., 1 d) as organocatalysts for electrophilic halogenation in heptane via a phase-transfer mechanism and proved that this catalytic scheme is applicable to a series of electrophilic bromination reactions. [15][16][17] We rationalized that 1H-indole-3-carboxylate with a water-solubilizing group could potentially be employed as a promising micellar phase-transfer organocatalyst for environmentally benign electrophilic bromination in water (Scheme 1). The development of highly hydrophilic indole catalysts allows the reactions to occur in water.…”

The C(sp3)–H bond functionalization of thioethers with styrenes with insight into the mechanism

“…Alkenes are versatile building blocks for the synthesis of various functional groups. 1 Alkene difunctionalization reactions, such as bromoesterification, 2 azidoarylation, 3 dialkylation 4 and trifluoromethylalkynylation, 5 etc . 6 can produce complex molecules via simple transformations.…”

Solvent and catalyst-free bromofunctionalization of olefins using a mechanochemical approach

“…27,28 Our previous work in this area include the use of lipophilic indole catalysts as a solid-to-liquid phase bromine shuttle for efficient bromination with N-bromoimide reagents in environmentally benign lipophilic solvent. [29][30][31] Despite these precedent efforts on establishing greener bromofunctionalization of olens, recycling solvents at a large scale is still highly energy-consuming and is undesirable at industrial sectors. In view of the ever-increasing demand for green chemical protocols, the development of more sustainable bromofunctionalization processes is still highly desired.…”