Titanocene‐Catalyzed [2+2] Cycloaddition of Bisenones and Comparison with Photoredox Catalysis and Established Methods
作者:Zhenhua Zhang、Julius B. Stückrath、Stefan Grimme、Andreas Gansäuer
DOI:10.1002/anie.202102739
日期:2021.6.21
Cp2Ti(TFA) is a broadly applicable catalyst for the [2+2] cycloaddition of bisenones by inner-sphere electron transfer. The attractiveness of this mechanism is shown by comparison with outer-sphere ET methods. DFT calculations show that the reaction proceeds through a unique unfavorable 5-exo (the rate-determining step) and a favorable 4-exo cyclization.
Stereoselective synthesis of spirooxindole derivatives using an organocatalyzed tandem Michael–Michael reaction
作者:Huicai Huang、Manisha Bihani、John C.-G. Zhao
DOI:10.1039/c5ob02348c
日期:——
A highly efficient stereoselective method for the synthesis of functionalized spirooxindole derivatives with three stereogenic centers was realized through an organocatalytic tandem Michael–Michael reaction. By employing (S)-α,α-diphenylprolinol trimethylsilyl ether as the catalyst and N,N′-bis[3,5-bis(trifluoromethyl)phenyl]thiourea as the cocatalyst, the reaction between N-tritylisatylidenemalononitriles
One-Pot Sequential Organocatalysis: Highly Stereoselective Synthesis of Trisubstituted Cyclohexanols
作者:Qipu Dai、Hadi Arman、John Cong-Gui Zhao
DOI:10.1002/chem.201203104
日期:2013.1.28
>99:1) and enantioselective (ee value up to 96 %) synthesis of trisubstituted cyclohexanols was achieved by using a one‐pot sequentialorganocatalysis that involved a quinidine thiourea‐catalyzed tandem Henry–Michael reaction between nitromethane and 7‐oxo‐hept‐5‐en‐1‐als followed by a tetramethyl guanidine (TMG)‐catalyzed tandem retro‐Henry–Henry reaction on the reaction products of the tandem Henry–Michael
Highly Stereoselective Synthesis of Trisubstituted Cyclohexanols Using a Guanidine-Catalyzed Tandem Henry–Michael Reaction
作者:Qipu Dai、Huicai Huang、John Cong-Gui Zhao
DOI:10.1021/jo4001806
日期:2013.4.19
A highly diastereoselective (dr >99:1) and enantioselective (ee value up to 98%) synthesis of trisubstituted cyclohexanols was achieved by using a tandem Henry–-Michael reaction between nitromethane and 7-oxo-hept-5-enals catalyzed by the Misaki–Sugimura guanidine.