Palladium catalyzed Suzuki cross-coupling of 3-iodo-2-(methylthio)-benzo[b]furan derivatives: synthesis of 3-aryl-2-(methylthio)benzo[b]furans

Abstract

Neste trabalho desenvolvemos um método seletivo e eficiente para a síntese de derivados de 3-aril-2-(tiometil)-benzo [b]furanos, via reação de acoplamento com ácidos borônicos, catalisada por paládio. As condições reacionais usadas foram brandas e compatíveis com ácidos borônicos contendo substituintes retiradores, doadores de elétrons ou neutros.A selective and efficient method for the synthesis of 3-aryl-2-(methylthio)benzo [b]furans derivatives by palladium catalyzed cross-coupling reaction with boronic acids has been developed. The reaction proceeded cleanly under mild conditions and was performed with aryl boronic acids bearing electron-withdrawing, electron donating and neutral substituents.

Synthesis of Alkynyl Sulfides by Copper-Catalyzed Thiolation of Terminal Alkynes Using Thiosulfonates

“…For example, tetracyclic 2-chloro­benzofuro­[2,3- b ]­benzo­furan ( 15 ) was successfully prepared from 5-chloro-3-iodo-2-methylthio­benzo­[ b ]­furan ( 9d ) by selective Suzuki–Miyaura cross-coupling at the iodo group, followed by oxidation of the methylthio group to methanesulfonyl and subsequent base-mediated cyclization (Figure B). Furthermore, benzofuran 9d was successfully subjected to a sequential three-step selective arylation that involved a palladium-catalyzed Suzuki–Miyaura cross-coupling at the iodo group, a nickel-catalyzed Kumada–Tamao–Corriu cross-coupling at the methylthio group, and a palladium-catalyzed Suzuki–Miyaura cross-coupling at the remaining chloro group (Figure C) . These transformations took place smoothly with high selectivity and efficiency, clearly showing the utility of benzofuran 9d as a platform molecule for the synthesis of diverse multifunctionalized benzofurans.…”