Asymmetric Synthesis of Axially Chiral Biaryls by Nickel-Catalyzed Grignard Cross-Coupling of Dibenzothiophenes
作者:Yong-Hwan Cho、Asato Kina、Toyoshi Shimada、Tamio Hayashi
DOI:10.1021/jo035880p
日期:2004.5.1
2-mercapto-2‘-substituted-1,1‘-biphenyls (8a−c) and 2-mercapto-2‘-substituted-1,1‘-binaphthyls (8d) in high yields. The mercapto group in the axially chiral cross-coupling products was converted into several functional groups by way of the methylsulfinyl group. The rate of flipping in dinaphthothiophene was measured by variable-temperature 31P NMR analysis of methylphenylphosphinyldinaphthothiophene derivative (21)
1,9-二取代的二苯并噻吩(6a - c)和二萘并噻吩(6d)与芳基和烷基格利雅试剂(7)的催化不对称格利雅交叉反应在存在a的情况下以高对映选择性(高达ee的95%)进行在THF中与2-二苯基膦-1,1'-联萘基(H-MOP)或恶唑啉-膦配体(i -Pr-phox)配位的镍催化剂(3-6 mol%)得到2-巯基-2'-取代的-1,1'-联苯(8a - c)和2-巯基-2'-取代的1,1'-联萘基(8d)高产。轴向手性交叉偶联产物中的巯基通过甲基亚磺酰基基团转化为几个官能团。通过对甲基苯基膦基二萘并噻吩衍生物(21)的可变温度31 P NMR分析来测量二萘并噻吩的翻转速率。