Synthesis of Chiral Polycyclic Tetrahydrocarbazoles by Enantioselective Aminocatalytic Double Activation of 2-Hydroxycinnamaldehydes with Dienals
作者:Yong-Chao Ming、Xue-Jiao Lv、Ming Liu、Yan-Kai Liu
DOI:10.1021/acs.orglett.1c02309
日期:2021.8.20
An efficient aminocatalytic enantioselective double-activation strategy has been developed that combines several different aminocatalytic modes in a cascade process, such as iminiumion, vinylogous iminiumion, trienamine, and dienamine activations. By using this strategy, 2-hydroxycinnamaldehydes worked well with various dienals via [4 + 2] cycloaddition and the oxa-Michael reaction-initiated cascade
Asymmetric organocatalytic vinylogous Michael addition triggered triple-cascade reactions of 2-hydroxycinnamaldehydes and vinylogous nucleophiles: construction of benzofused oxabicyclo[3.3.1]nonane scaffolds
作者:Hui-Chun Wu、Chen Wang、Ying-Han Chen、Yan-Kai Liu
DOI:10.1039/d0cc07761e
日期:——
An organocatalytic vinylogous Michael addition triggered triple-cascade reaction has been developed. 2-Hydroxycinnamaldehydes worked under iminiumactivation with either acyclic or cyclic ketone-derived α,α-dicyanoalkenes, yielding the benzofused oxabicyclo[3.3.1]nonanes bearing one quaternary stereocenter with excellent stereoselectivities.
The highly efficient enantioselective [4 + 2] cycloaddition of o-QMs with ortho-hydroxyphenyl-substituted α,β-unsaturated compounds was realized by using a chiral N,N′-dioxide-Sc(III) complex as catalyst. A variety of chiral chromane derivatives with three continuous stereocenters were obtained in excellent results (up to 99% yield, >19:1 dr, and 99% ee) under as low as 0.005–1 mol % catalyst loading
Organocatalytic asymmetric cascade cyclization reaction of o-hydroxy cinnamaldehydes with diphenylphosphine oxide
作者:Haiyun Sun、Yuan Li、Wei Liu、Yang Zheng、Zhengjie He
DOI:10.1016/j.cclet.2018.01.026
日期:2018.11
highly stereoselective asymmetriccascade cyclization reaction between o-hydroxycinnamaldehydes and diphenylphosphine oxide has been achieved with 84%–99% ee and 7:1-20:1 dr under the catalysis of l -diarylprolinol silyl ether. This reaction provides a facile access to highly enantioenriched 4-diphenylphosphinyl chroman-2-ols. It also represents a novel organocatalyticasymmetric phospha-Michael addition
Trimethylsilyl Iodide Mediated One-Pot Synthesis of 2-Allyl-2<i>H</i>-chromenes
作者:Birakishore Padhi、D. Srinivas Reddy、Debendra K. Mohapatra
DOI:10.1002/ejoc.201403240
日期:2015.1
A new and efficient metal-free trimethylsilyl iodide (TMSI) catalyzed one-pot synthesis of 2-allyl-2H-chromenes has been developed that takes place under mild conditions. The synthesis proceeds through a Wittig reaction by using (triphenylphosphoranylidene)acetaldehyde to form an o-hydroxycinnamaldehyde derivative followed by a tandem isomerization and C–O and C–C bond-forming reactions. The procedure