Enantioselective Bromolactonization of Trisubstituted Olefinic Acids Catalyzed by Chiral Pyridyl Phosphoramides
作者:Yasuhiro Nishikawa、Yuhta Hamamoto、Rika Satoh、Naho Akada、Shuhei Kajita、Marina Nomoto、Megumi Miyata、Madoka Nakamura、Chinatsu Matsubara、Osamu Hara
DOI:10.1002/chem.201804630
日期:2018.12.17
Enantioselective bromolactonization of trisubstituted olefinic acids producing synthetically useful chiral lactones with two contiguous asymmetric centers has remained mainly unexplored except for the 6‐exo cyclization mode. In this work, the 5‐exo‐ and 6‐endo modes of bromocyclization of trisubstituted olefinic acids were enabled for the first time using N‐bromosuccinimide and a pyridyl phosphoramide
除6- exo环化方式外,三取代烯烃生产具有两个连续不对称中心的合成有用的手性内酯的对映选择性溴内酯化主要仍未开发。在这项工作中,使用N首次启用了三取代烯烃的溴环化的5-外和6-内环模式。-溴代琥珀酰亚胺和吡啶基磷酰胺催化剂。通过利用反应性烷基溴化物部分进行转化而不丧失立体化学信息,证明了所得溴内酯的实用性。优化研究和对照实验表明,磷酰胺物种中吡啶部分的碱性和NH质子的存在强烈影响反应性和对映选择性参数。