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
Chiral Squaramide-Catalyzed Sulfa-Michael/Aldol Cascade for the Asymmetric Synthesis of Spirocyclic Tetrahydrothiophene Chromanone Derivatives
作者:Bo-Liang Zhao、Lei Liu、Da-Ming Du
DOI:10.1002/ejoc.201402889
日期:2014.12
A bifunctional squaramide-catalyzed sulfa-Michael/aldol cascadereaction between benzylidenechroman-4-ones and 1,4-dithiane-2,5-diol with a low catalyst loading has been developed. This reaction constitutes a facile asymmetricsynthesis of chiral spirocyclic tetrahydrothiophene chromanone derivatives with three contiguous stereocenters in high to excellent yields (up to 99 %) and with high enantioselectivities