Chiral Squaramide-Catalyzed Michael/Alkylation Cascade Reaction for the Asymmetric Synthesis of Nitro-Spirocyclopropanes
作者:Bo-Liang Zhao、Da-Ming Du
DOI:10.1002/ejoc.201500533
日期:2015.8
diastereoselective and enantioselective cyclopropanation reaction has been developed by employing a Michael/alkylationcascadereaction between (E)-3-arylenechroman-4-one or (E)-2-arylideneindan-1-one derivatives and a bromonitroalkane with a chiral squaramide catalyst. This reaction constitutes a facile asymmetricsynthesis for nitro-spirocyclopropanes that have three adjacent stereogenic centers, including
Enantioselective heterocyclic synthesis of spiro chromanone–thiochroman complexes catalyzed by a bifunctional indane catalyst
作者:Yaojun Gao、Qiao Ren、Hao Wu、Maoguo Li、Jian Wang
DOI:10.1039/c0cc03489d
日期:——
benzylidenechroman-4-ones and 2-mercaptobenzaldehydes for efficient construction of spiro chromanone-thiochroman complexes were accomplished with high yields and excellent selectivities via a novel bifunctional indane catalyst.
Enantioselective Synthesis of Densely Functionalized Pyranochromenes via an Unpredictable Cascade Michael-Oxa-Michael-Tautomerization Sequence
作者:Qiao Ren、Yaojun Gao、Jian Wang
DOI:10.1002/chem.201002490
日期:2010.12.10
A surprising example of enantioselectivecascade Michael–oxa‐Michael–tautomerization reactions of malononitrile and benzylidenechromanones has been developed. In this case, malononitrile functions as both nucleophile and electrophile. Meanwhile, a simple bifunctional indane amine–thiourea catalyst has been discovered to promote this process to afford high yields (up to 99%) and high to excellent enantiomeric
Facile synthesis of spiro chromanone-tetrahydrothiophenes with three contiguous stereocenters via sulfa-Michael/aldol cascade reactions
作者:Ya-Jian Hu、Xiao-Bing Wang、Su-Yi Li、Sai-Sai Xie、Kelvin D.G. Wang、Ling-Yi Kong
DOI:10.1016/j.tetlet.2014.11.026
日期:2015.1
A novel sulfa-Michael/aldol cascade reaction of (E)-3-arylidenechroman-4-ones with 1,4-dithiane-2,5-diol has been developed. This method provides a new practical and facile approach to 4′-hydroxy-2′-aryl-4′,5′-dihydro-2′H-spiro[chroman-3,3′-thiophen]-4-ones with three contiguous stereocenters in high yields. The transformation is atom-economic with good to excellent diastereoselectivities.
Substituted 3-<i>E-</i>Styryl-2<i>H</i>-chromenes and 3-<i>E-</i>Styryl-2<i>H</i>-thiochromenes: Synthesis, Photophysical Studies, Anticancer Activity, and Exploration to Tricyclic Benzopyran Skeleton
of densely substituted 2H-chromenes and 2H-thiochromenes were synthesized in good yield through cyanuric chloride-dimethylformamide mediated cleavage of different spiro-4-hydroxychroman-3,1′-cyclopropanes and similar thiochroman analogues. This protocol involves operationally very simple, facile and cost-effective reactions using easily accessible reagents under mild reaction condition with tolerance