Synthesis and Stereodynamics of Highly Constrained 1,8-Bis(2,2‘-dialkyl-4,4‘-diquinolyl)naphthalenes
作者:Gilbert E. Tumambac and、Christian Wolf
DOI:10.1021/jo035547l
日期:2004.3.1
8-dibromonaphthalene and 2-alkyl-4-trimethylstannylquinolines. Optimization of the cross-coupling reaction allowed the preparation of highly constrained 1,8-bis(2,2‘-dimethyl-4,4‘-diquinolyl)naphthalene, 2, and 1,8-bis(2,2‘-diisopropyl-4,4‘-diquinolyl)naphthalene, 3, in 42% and 41% yield, respectively. Employing Pd(PPh3)4 and CuO as the cocatalysts in the coupling reaction of 1,8-dibromonaphthalene and 2-
轴向手性的1,8-二喹啉基萘的顺式和反式异构体是通过Pd催化的1,8-二溴萘与2-烷基-4-三甲基锡烷基喹啉的Stille偶联而合成的。交叉偶联反应的优化允许制备高度受限的1,8-双(2,2'-二甲基-4,4'-二喹啉基)萘2和1,8-双(2,2'-二异丙基) -4,4'-二喹啉基)萘3的产率分别为42%和41%。在1,8-二溴萘与2-烷基-4-三甲基锡烷基喹啉的偶合反应中,使用Pd(PPh 3)4和CuO作为助催化剂被证明优于PdCl 2(dppf),Pd 2(dba)等其他催化剂。3 / P(吨)3和POPd。发现2和3的C 2对称反异构体比相应的内消旋同分异构体更稳定。通过NMR和HPLC分析确定两种对映异构体抗构象体与顺式构象体的比例对于2为7.9:1,对于3为8.6:1 。发现2和3的阻转异构体在室温下对于绕手性轴旋转是稳定的,并且在Chiralpak AD柱上通过半制备性HPL