(<i>Z</i>
)-Enol <i>p</i>
-Tosylate Derived from Methyl Acetoacetate: A Useful Cross-Coupling Partner for the Synthesis of Methyl (<i>Z</i>
)-3-Phenyl (or Aryl)-2-Butenoate
作者:Yuichiro Ashida、Hidefumi Nakatsuji、Yoo Tanabe
DOI:10.1002/0471264229.os094.08
日期:——
Highly efficient synthesis of chiral aromatic ketones via Rh-catalyzed asymmetric hydrogenation of β,β-disubstituted enones
A succinct and efficient protocol was developed for the synthesis of chiral aromatic ketones via asymmetric hydrogenation of β,β-disubstitutedenones with rhodium catalysts based on chiral bisphosphine thiourea ligands. A series of substrates (17 examples) was smoothly catalyzed to afford the corresponding chiral aromatic ketones in high conversions(>99%)with excellent enantioselectivities (up to 96%
General, Robust, and Stereocomplementary Preparation of β-Ketoester Enol Tosylates as Cross-Coupling Partners Utilizing TsCl−<i>N</i>-Methylimidazole Agents
(Z)-stereocomplementary enol tosylation of beta-ketoesters using TsCl- N-methylimidazole (NMI)-Et3N or LiOH. TsCl coupled with NMI formed a highly reactive N-sulfonylammonium intermediate. Stereocongested secondary alcohols were smoothly sulfonylated using Ts(Ms)Cl-NMI-Et3N. beta-Ketoesters underwent (E)-selective tosylation using TsCl-NMI-Et3N and (Z)-selective tosylation using TsCl-NMI-LiOH (total