Asymmetric Nitroaldol Reactions of Nitroalkanes with Isatins Catalyzed by Bifunctional Cinchona Alkaloid Derivatives
作者:Mei-Qiu Li、Jin-Xin Zhang、Xiao-Fei Huang、Bin Wu、Zhao-Min Liu、Jian Chen、Xiang-Dong Li、Xing-Wang Wang
DOI:10.1002/ejoc.201100824
日期:2011.9
The enantioselective nitroaldolreactions of isatins with nitroalkanes were smoothly carried out by organocatalysis. A C6′-OH cinchona alkaloid derivative bearing a C9-OBn group exhibited outstanding catalytic efficiency as an acid–base bifunctional catalyst for the nitroaldolreaction of isatins with nitromethane, providing 3-hydroxy-3-(nitromethyl)indolin-2-ones in good yields (90–98 %) and with
hybrid-type squaramide-fused aminoalcohol (SFAA) catalysts were synthesized, and their catalytic efficiency in the enantioselective nitro-aldol reaction of various isatins with nitromethane has been described. This transformation afforded chiral 3-substituted 3-hydroxyoxindoles in excellent chemical yields (up to 99 %) with high enantioselectivities (up to 95 % ee). The resulting chiral 3-hydroxyoxindoles can
Biscinchona alkaloid catalysed Henry reaction of isatins: Enantioselective synthesis of 3-hydroxy-3-(nitromethyl)indolin-2-ones
作者:Parvathaneni Sai Prathima、Keesara Srinivas、Kodicherla Balaswamy、Racha Arundhathi、Gajjaia Narsimha Reddy、Balasubramanian Sridhar、Mandapati Mohan Rao、Pravin R. Likhar
DOI:10.1016/j.tetasy.2011.11.008
日期:2011.12
The direct catalytic enantioselective Henry (nitroaldol) reaction of isatins with nitromethane has been developed in the presence of a biscinchona alkaloid as a chiral organocatalyst. The resulting Henry adducts bearing C3-quaternary stereocentres were obtained in high yields (up to 94%) with high enantioselectivities (up to 97% ee). (C) 2011 Elsevier Ltd. All rights reserved.
Catalytic Enantioselective Henry Reactions of Isatins: Application in the Concise Synthesis of (
<i>S</i>
)‐(−)‐Spirobrassinin
作者:Lu Liu、Shilei Zhang、Fei Xue、Guangshun Lou、Haoyi Zhang、Shichao Ma、Wenhu Duan、Wei Wang
DOI:10.1002/chem.201101025
日期:2011.7.4
highly efficient, cupreine‐catalyzed, enantioselective Henry reaction of readily available isatins and nitroalkanes has been developed (see scheme). The products are produced in excellent yields and good enantioselectivities under mild reaction conditions and without chromatography. The utility of the strategy has been demonstrated in the facile synthesis of (S)‐(−)‐spirobrassinin without the need for