Pentanidium–Catalyzed Enantioselective α-Hydroxylation of Oxindoles Using Molecular Oxygen
摘要:
Pentanidium-catalyzed alpha-hydroxylation of 3-substituted-2-oxindoles using molecular oxygen has been developed with good yields and enantioselectivities. This reaction does not require an additional reductant such as triethyl phosphite, which was typically added to reduce the peroxide intermediate. The reaction was demonstrated to consist of two-steps: an enantioselective formation of hydroperoxide oxindole and a kinetic resolution of the hydroperoxicle oxindole via reduction with enolates generated from the oxindoles.
Enantioselective Synthesis of Quaternary Carbon Stereocenters: Addition of 3-Substituted Oxindoles to Vinyl Sulfone Catalyzed by Pentanidiums
作者:Lili Zong、Shubo Du、Kek Foo Chin、Chao Wang、Choon-Hong Tan
DOI:10.1002/anie.201503844
日期:2015.8.3
3‐alkyloxindoles to phenyl vinyl sulfone has been demonstrated. This approach allows the construction of 3,3‐dialkyl‐substituted oxindole frameworks with high yield and excellent enantioselectivity (up to 99 %) under simple phase‐transfer conditions. A variety of oxindoles bearing all‐carbonquaternary stereogenic centers were obtained in the presence of 0.25 mol % pentanidium. Meanwhile, practicality was
Pentanidium catalyzed enantioselective hydroperoxidation of 2-oxindole using molecular oxygen
作者:Shun Zhou、Lin Zhang、Chun Li、Yuanhu Mao、Jianta Wang、Ping Zhao、Lei Tang、Yuanyong Yang
DOI:10.1016/j.catcom.2016.04.016
日期:2016.7
Pentanidium catalyzed enantioselective 3-hydroperoxidation of 2-oxindoles with molecularoxygen has been established. Various 3-hydroperoxy-2-oxindoles were achieved in good ee and yield.