A new approach to the synthesis of 2-vinylthiophenes and selenophenes; competition between free radical and anionic cycloaromatization of bridged di- and tetrapropargylic sulfides and selenides
作者:Yossi Zafrani、Marina Cherkinsky、Hugo E Gottlieb、Samuel Braverman
DOI:10.1016/s0040-4020(03)00327-2
日期:2003.4
presence of t-BuOK in dry THF these compounds underwent isomerization to the corresponding diallenes, followed by a tandem anionic cyclization and aromatization to 2-vinylthiophene or selenophene derivatives. Some mechanistic studies indicated competition between free radical and anionic cycloaromatization. The latter is influenced by the nature of the bridging heteroatom, substitution of the allenyl group
已经制备了一系列未知的二炔丙基和四炔丙基硫化物和硒化物。在干燥的THF中在t- BuOK存在下,这些化合物进行异构化为相应的二烯,然后进行串联阴离子环化并芳构化为2-乙烯基噻吩或硒基衍生物。一些机理研究表明,自由基和阴离子环芳构化之间存在竞争。后者受桥接杂原子的性质,烯丙基的取代和碱浓度的影响。