Eisler Sara, Chahal Navjot, McDonald Robert, Tykwinski Rik R
Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada.
Chemistry. 2003 Jun 6;9(11):2542-50. doi: 10.1002/chem.200204584.
The synthesis of conjugated polyyne structures via a modification of the Fritsch-Buttenberg-Wiechell (FBW) rearrangement is reported. Our adaptation provides for the 1,2-migration of an alkyne in a carbene/carbenoid intermediate that is conveniently effected via lithium-halogen exchange with the appropriate dibromo-olefinic precursor. This rearrangement is quite rapidly accomplished under mild conditions (hexane solution, -78 degrees C), and the seemingly high migratory aptitude of the alkynyl moiety provides for efficient rearrangement. This, in turn, allows for multiple rearrangements in a single molecule, greatly facilitating the construction of highly unsaturated substrates. This procedure is exploited for the rapid synthesis of symmetrical and unsymmetrical 1,3,5-hexatriynes, extended polyynes, and aryl polyyne building blocks. Most significantly, many of these structures have been or would be difficult to access via more traditional transition metal catalyzed homo- or cross-coupling techniques.
报道了通过对弗里茨希-布滕贝格-维切尔（FBW）重排进行修饰来合成共轭聚炔结构。我们的改进方法实现了卡宾/类卡宾中间体中炔烃的1,2-迁移，这可通过与适当的二溴烯烃前体进行锂-卤素交换方便地实现。这种重排在温和条件下（己烷溶液，-78℃）能相当迅速地完成，炔基部分看似较高的迁移能力使得重排高效进行。这反过来又允许在单个分子中进行多次重排，极大地促进了高度不饱和底物的构建。该方法被用于快速合成对称和不对称的1,3,5-己三炔、扩展聚炔以及芳基聚炔结构单元。最重要的是，这些结构中的许多通过更传统的过渡金属催化的均相或交叉偶联技术难以获得或根本无法获得。
