Catalytic enantioselective 5-endo-bromocycloetherification of unactivated cyclic alkenes
作者:Haoran Xiong、Kei Yoshida、Kosuke Okada、Hirofumi Ueda、Hidetoshi Tokuyama
DOI:10.1016/j.tetlet.2022.153906
日期:2022.7
and good to high enantioselectivity. Results show that the enantioselectivity depends on the solvent system and substituents at the 3,3′-position of the catalyst. Thus, the best result can be obtained using a catalyst that has 2,4,6-tricyclohexylphenyl groups at the 3,3′-positions in a mixture of fluorobenzene and n-heptane. In addition, the construction of a quaternary carbon center with the retention
本研究报告了催化对映选择性 5 -endo-trig 溴环醚化具有羟乙基的六元未活化烯烃。所提出的反应发生在手性阴离子相转移催化体系中,使用基于联萘酚的手性磷酸和 DABCO 溴络合物衍生物的组合提供双环四氢呋喃稠合 6 元产物,其在桥头处带有溴基团位置具有完全的非对映选择性和良好的对映选择性。结果表明,对映选择性取决于溶剂体系和催化剂3,3'-位的取代基。因此,在氟苯和n-庚烷。此外,还报道了通过产物中叔溴基团的自由基介导烯丙基化来构建季碳中心并保留构型。