Síntese de derivados de benzo[b]furano promovida por t-BuOK

• Main Author: Pinheiro, Roberto do Carmo
• Publication Date: 2023
• Format: Doctoral thesis
• Language: por
• Source: Manancial - Repositório Digital da UFSM
• dARK ID: ark:/26339/0013000006xpn
• Download full: http://repositorio.ufsm.br/handle/1/29201
• topic: Heterociclos; Base; Ciclização; Reações em cascata; Benzofuranos; Heterocycle; Cyclization; Tandem reactions; Benzofurans; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA

In this work, we report the study developed for the preparation of benzo[b]furan derivatives via intramolecular double cyclization reaction promoted by tert-BuOK. First, 3- ((butylselanyl)methyl)-2-(phenylethynyl)benzofuran and 3-methyl-2- (phenylethynyl)benzofuran derivatives were selectively synthesized by reacting 1- (phenylethynyl)-2-((2-(phenylethynyl)benzyl)oxy)benzene with t-BuOK in different solvents. Furthermore, 4-iodo-3-phenyl-1H-selenopyrano[4,3-b]benzofuran derivatives were synthesized through further iodocyclization. In the second half of this work, 1-(phenylethynyl)- 2-((2-(phenylethynyl)benzyl)oxy)benzene derivatives were subjected to a tandem carbocyclization reaction with t-BuOK, leading to the synthesis of 6,7-diphenyl- 5Hbenzo[6,7]cyclohepta[1,2-b]benzofurans in good yields. Both elaborated methodologies took place selectively through a 5-exo-dig intramolecular cyclization for the formation of benzo[b]furans and, in the second half of this work, a 7-endo-dig cyclization, providing the benzo[b]furans fused to a 7-membered carbocycle in a one-pot procedure.