A One-Pot Sequence of Stille and Heck Couplings: Synthesis of Various 1,3,5-Hexatrienes and Their Subsequent 6π-Electrocyclizations
作者:Paultheo von Zezschwitz、Frauke Petry、Armin de Meijere
DOI:10.1002/1521-3765(20010917)7:18<4035::aid-chem4035>3.0.co;2-p
日期:2001.9.17
Palladium-catalyzed cross-coupling reactions of 2-bromocyclohex-1-enyl triflates 7 and 11 with a variety of alkenylstannanes occurred chemoselectively at the site of the triflate leaving group to give bromobutadienes which readily underwent Heck reactions with acrylates and styrene. Both steps could be performed in the same flask to give differentially functionalized hexatrienes in up to 88% overall
在三氟甲磺酸酯离去基团的位点,钯催化的2-溴环己基-1-烯基三氟甲磺酸酯7和11与各种烯基锡烷的化学偶联反应产生了溴丁二烯,这些溴丁二烯易于与丙烯酸酯和苯乙烯进行Heck反应。这两个步骤都可以在同一烧瓶中进行,从而以高达88%的总收率得到差异化官能化的己三烯。对于简单的锡烷,可以将相同的催化剂前体用于两个偶联步骤,从而仅用一份催化剂即可完成整个序列。对于某些官能取代的锡烷,必须使用经过特殊调节的催化剂体系。将所得的1,3,5-己三烯进一步转化,特别是将甲氧基取代的化合物14a-c转化为双环[4.4.0]癸烯30(71-97%),双环[4.3.0]壬烯酮35(74-93%),环癸炔酮37a(47%)和环壬炔酮39a(15%)。其他己三烯的热电环化以良好的收率得到四氢萘31(60-61%),三环内酯32(72-75%)和十氢菲33(75%)。