A novel synthesis of calix[4]thiophenes and calix[4]furans
作者:Gon-Ann Lee、Wen-Chieh Wang、Minghuey Shieh、Ting-Shen Kuo
DOI:10.1039/c0cc00437e
日期:——
The addition of heteroaryllithium to various ketones followed by dehydration gave 1-(2-heteroaryl)cycloalkenes and (2-hetero- aryl)alkenes. When alkenes were treated with 10 mol% NIS, calix[4]thiophenes and calix[4]furans were obtained in good yields.
The oxidation of macrocyclic thiophenes, such as the calix[4]thiophenes, with m-chloroperbenzoic acid in the presence of BF3·OEt2 afforded the remarkably stable mono- and bis-S-oxides based on their X-ray crystal structures. The stable mono-S-oxide of the calix[4]thiophene reacted with dimethyl acetylenedicarboxylate at 160 °C to form the thiophene-S,C-sulfonium ylide, indicating that the cycloaddition