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
Organocatalytic asymmetric Michael/hemiacetalization/acyl transfer reaction of α-nitroketones with <i>o</i>-hydroxycinnamaldehydes: synthesis of 2,4-disubstituted chromans
作者:Rajendra Maity、Subhas Chandra Pan
DOI:10.1039/c8ob00078f
日期:——
An organocatalyticasymmetriccascadeMichael/hemiketalization/acyl transfer reaction between o-hydroxycinnamaldehydes and α-nitroketones is developed. Prolinol TMS ether catalyst in combination with benzoic acid was found to be the most effective for this reaction which proceeds through an equilibrium of lactols to provide a single diastereomer of enantiopure 2,4-disubstituted chromans.
Asymmetric Organocatalytic Michael Addition-Cyclization Cascade Reaction of Nitroalkanes with o-Hydroxycinnamaldehydes
作者:Kwang-Su Choi、Sung-Gon Kim
DOI:10.1002/ejoc.201101794
日期:2012.2
A catalytic enantioselective Michaeladdition–cyclizationreaction of nitroalkanes with o-hydroxycinnamaldehydes has been established by using a diphenylprolinol TMS ether as an organocatalyst. The reaction afforded the corresponding 4-substituted chroman-2-ols in excellent yields with high levels of enantioselectivities (95 to >99 % ee).
Regioselective Control of 1,2- Versus 1,4-Addition in Organocatalytic Reactions of o-Hydroxycinnamaldehydes with Organoboronic Acids
作者:Sung-Gon Kim、Kwang-Su Choi
DOI:10.1055/s-0030-1258268
日期:2010.12
The regioselective 1,2-addition and 1,4-addition reactions of o-hydroxycinnamaldehydes with organoboronic acids in the presence of organocatalysts gave 2-substituted 2H-chromenes and 4-substituted chroman-2-ols, respectively. Diethylamine was used as the catalyst for the 1,4-addition reaction, whereas dibenzylamine and trichloroacetic acid were used as the catalyst and additive, respectively, in the
Asymmetric organocatalytic reactions of o-hydroxycinnamaldehydes with organoboronic acids: a facile enantioselective access to chromanes and dihydrobenzopyranes
作者:Kwang-Su Choi、Sung-Gon Kim
DOI:10.1016/j.tetlet.2010.07.138
日期:2010.9
4-addition reactions of organoboronic acids to o-hydroxycinnamaldehydes, which afford chromanes and dihydrobenzopyranes, have been established using an organocatalyst derived from imidazolidinone. The chromanes have been obtained in high chemical yields and enantioselectivities and can be readily used to obtain a variety of chromane derivatives through subsequent transformations.