Abstract

Aryl-substituted heteroaromatics play a key role in medicinal chemistry, natural products, advanced materials, and the agrochemical industry. Therefore, developing novel methods to access these scaffolds is of the upmost importance. The most common methods to access these scaffolds are through palladium-catalyzed cross-coupling reactions. Classically, these methods used harsh conditions and dangerous organometallic compounds; however, more recently an emphasis on using less harsh conditions and environmentally safe compounds has pushed towards developing novel methodologies. Palladium-catalyzed desulfinative and decarboxylative cross-couplings have emerged as powerful alternatives to the classical methods, yielding environmentally benign by-products with high atom economy and great efficiency. These methods use carboxylic acids and sulfonates as nucleophilic coupling partners with aryl-halides as the electrophilic partner.
To expand the desulfinative methodology, synthetically versatile aryl triflates have been employed as electrophilic coupling partners. Good yields were obtained in aqueous and alcoholic media without the use of base, additives, or co-catalysts. Furthermore, mechanistic studies on the decarboxylative cross-coupling have been investigated using computational methods. Density functional theory (DFT) was used to determine the complete reaction profile as well as transition states. It was determined that the key decarboxylation step occurs via an electrophilic aromatic substitution reaction. These results are important for the development of alternative methods and the advancement of our current understanding of these methodologies.