Six- and Eightfold Palladium-Catalyzed Cross-Coupling Reactions of Hexa- and Octabromoarenes
作者:Baldur Stulgies、Peter Prinz、Jörg Magull、Karsten Rauch、Kathrin Meindl、Stephan Rühl、Armin de Meijere
DOI:10.1002/chem.200400723
日期:2005.1
Palladium-catalyzed sixfold coupling of hexabromobenzene (20) with a variety of alkenylboronates and alkenylstannanes provided hexaalkenylbenzenes 1 in up to 73 % and 16 to 41 % yields, respectively. In some cases pentaalkenylbenzenes 21 were isolated as the main products (up to 75 %). Some functionally substituted hexaalkenylbenzene derivatives containing oxygen or sulfur atoms in each of their six
钯催化六溴代苯(20)与各种烯基硼酸酯和烯基锡酮的六重偶联分别提供了六烯基苯1,产率分别高达73%和16%至41%。在某些情况下,五烯基苯21被分离为主要产物(最高含量为75%)。还已经制备了一些在其六个臂中的每个臂中含有氧或硫原子的官能取代的六烯基苯衍生物(16%至24%的产率)。较少空间阻碍的2,3,6,7,10,11-六溴代三亚苯基(24)的六倍偶联以93%的收率得到了所需的六(3,3-二甲基-1-丁烯基)三亚苯基(25)。八溴萘(26)的首次成功的交叉偶联反应以21%的收率得到了八-(3,3-二甲基-1-丁烯基)萘(27)。晶体结构分析表明,根据取代基的性质,这六个臂与1a和1i一样全部位于中心苯环的同一侧,从而使它们成杯形分子,或者在1h和23中交替地位于中心平面的上方和下方。在27中, C-1,4,6,7的四个臂向下,其他的臂向上,反之亦然。催化氢化后,1 a产生89%的六(叔