The catalytic asymmetricepoxidation of 2‐arylidene‐1,3‐diketones using aqueous 30% H2O2 as oxidant has been successfully realized by a N,N′‐dioxide–scandium(III) triflate [Sc(OTf)3] complex, giving the corresponding products in moderate to good yields (up to 85%) with excellent enantioselectivities (up to 99% ee) under mild reaction conditions without extra additives.
N,N'-二氧化物-三氟甲磺酸scan [Sc(OTf)3 ]配合物已成功实现了使用30%H 2 O 2水溶液作为氧化剂催化2-亚芳基-1,3-二酮的催化不对称环氧化。,在温和的反应条件下,无需额外的添加剂,即可以中等至良好的收率(高达85%)提供具有良好对映选择性(高达99%ee)的相应产品。
Synthesis of Functionalized Furans via Chemoselective Reduction/Wittig Reaction Using Catalytic Triethylamine and Phosphine
作者:Chia-Jui Lee、Tzu-Hsiu Chang、Jhen-Kuei Yu、Ganapuram Madhusudhan Reddy、Ming-Yu Hsiao、Wenwei Lin
DOI:10.1021/acs.orglett.6b01781
日期:2016.8.5
An efficient protocol for the synthesis of highly functionalized furans via intramolecular Wittigreaction has been developed using catalytic amounts of phosphine and triethylamine. Silyl chloride served as the initial promoter to activate the phosphine oxide. Reduction of the activated phosphine oxide by hydrosilane resulted in generation of phosphine, while decomposition of Et3N·HCl resulted in regeneration
Regioselective
<scp>aza‐Michael</scp>
additions of
<scp>2‐arylidene</scp>
‐1,3‐diphenylpropan‐1,3‐diones with isatins: Synthesis of
<scp>N‐diketone</scp>
‐functionalized isatins
作者:Ya Cheng、Zheng Li
DOI:10.1002/jhet.4075
日期:2020.10
The efficient aza‐Michaeladditions of isatins to 2‐arylidene‐1,3‐diphenylpropan‐1,3‐diones at room temperature in the presence of cesium carbonate are described. The salient features of this protocol are no transition‐metal catalysts, mild conditions, high regioselectivity, high atom economy, satisfactory yield and simple work‐up procedures.