Steric influence of N-phosphorus-arylimines on the rhodium-catalyzed asymmetric arylation
作者:Xinyu Hao、Qian Chen、Ken-ichi Yamada、Yasutomo Yamamoto、Kiyoshi Tomioka
DOI:10.1016/j.tet.2011.06.033
日期:2011.9
Examination of the rhodium-catalyzed asymmetric arylation of benzaldehyde-imines bearing ethoxy, isopropoxy, phenyl, cyclohexyl, 3,5-xylyl, and 2,4,6-mesityl N-phosphorus activating/protecting groups revealed that bulky N-phosphorus groups retarded the arylation and at the same time prevented the competitive hydrolysis of an imine. Although the level of enantioselectivity was dependent favorably on
铑催化的带有乙氧基,异丙氧基,苯基,环己基,3,5-二甲苯基和2,4,6-间苯三甲酰N-磷活化/保护基的苯甲醛-亚胺的铑不对称芳基化反应表明,庞大的N-磷基团被阻滞了芳基化,同时阻止了亚胺的竞争性水解。尽管对映选择性水平良好地依赖于从88%ee至53%ee的膨松度,但是反应性随着蓬松度从95%至3%而急剧降低。