Li Chia-Wen, Wang Cheng-I, Liao Hsin-Yi, Chaudhuri Rupsha, Liu Rai-Shung
Department of Chemistry, National Tsing-Hua University, Hsinchu, Taiwan, ROC.
J Org Chem. 2007 Nov 23;72(24):9203-7. doi: 10.1021/jo701504m. Epub 2007 Nov 1.
We report a facile synthesis of functionalized dibenzo[g,p]chrysenes via initial ICl-promoted cyclization of bis(biaryl)acetylenes, followed by the Mizoroki-Heck coupling reaction. This new approach works well for various bis(biaryl)acetylenes to afford dibenzo[g,p]chrysenes bearing various functionalities. With substrates of one special type including 4'-methoxy-2-ethynylbiphenyls, we found that the ICl treatment led to ipso cyclization to give bicyclic spirocyclohexadienones. In the presence of MeOH/H2SO4, these spiroketone products undergo rearrangement to give 9-iodophenanthrenes through a selective 1,2-alkenyl migration. We prepared various 4'-methoxy-2-ethynylbiphenyl compounds to show the generalization of such an ipso cyclization and 1,2-alkenyl shift. This ipso-cyclization approach can be extended to the preparation of dibenzo[g,p]chrysenes.
我们报道了一种通过双（联芳基）乙炔的初始ICl促进环化，然后进行Mizoroki-Heck偶联反应来简便合成功能化二苯并[g,p]chrysenes的方法。这种新方法对各种双（联芳基）乙炔都能很好地起作用，以得到带有各种功能基团的二苯并[g,p]chrysenes。对于包括4'-甲氧基-2-乙炔基联苯在内的一种特殊类型的底物，我们发现ICl处理导致本位环化，生成双环螺环环己二烯酮。在MeOH/H2SO4存在下，这些螺环酮产物通过选择性的1,2-烯基迁移发生重排，生成9-碘菲。我们制备了各种4'-甲氧基-2-乙炔基联苯化合物，以展示这种本位环化和1,2-烯基迁移的普遍性。这种本位环化方法可以扩展到二苯并[g,p]chrysenes的制备。
