使用HCO 2 H / Et 3 N混合物作为氢源和定义明确的手性Rh催化剂(S,S)-或(R,R)-2,对环状氨基磺酸亚胺4和9进行不对称转移氢化(ATH), Cp * RhCl(TsDPEN)可在室温下0.5h内以优异的收率和对映选择性有效生产相应的环状氨基磺酸酯。具有预先存在的立体生成中心的4,5-二取代的亚胺9的ATH显示以动态动力学拆分发生。
1,6-Addition of vinyl <i>p</i>-quinone methides with cyclic sulfamidate imines: access to 4-hydroxyaryl-2,6-diarylpyridines
作者:Soumitra Guin、Santosh K. Gudimella、Sampak Samanta
DOI:10.1039/c9ob02708d
日期:——
wide range of symmetrically and unsymmetrically 2,4,6-trisubstitutedpyridines possessing a sterically hindered phenolic moiety at the C4-position with a broad substrate scope. This domino [3 + 3] cyclization reaction gives rise to several compatible functionalities under metal-free conditions. Finally, the large-scale synthesis of pyridinederivatives has been demonstrated.
Using Pd(CF3CO2)(2)/(SS)-f-binaphane as the catalyst, an efficient enantioselective synthesis of cyclic sulfamidates was developed via asymmetric hydrogenation of the corresponding cyclic imines in 2,2,2-trifluoroethanol at room temperature with high enantioselectivities (up to 99% ee).