Chemoselective N-Heterocyclic Carbene-Catalyzed Cascade of Enals with Nitroalkenes
作者:Zijun Wu、Xu Wang、Fangyi Li、Jicheng Wu、Jian Wang
DOI:10.1021/acs.orglett.5b01692
日期:2015.7.17
An unprecedented N-heterocycliccarbenecatalyzed chemoselective and enantioselective cascade reaction of enals with nitroalkenes has been developed. A wide range of enantioenriched dihydrocoumarins has been prepared, and the reaction goes through an enolate intermediate generated under a catalytic process.
Hauser-Kraus Annulation of Phthalides with Nitroalkenes for the Synthesis of Fused and Spiro Heterocycles
作者:Tarun Kumar、Nishikant Satam、Irishi N. N. Namboothiri
DOI:10.1002/ejoc.201600390
日期:2016.7
Hauser–Kraus annulation of sulfonylphthalides with simple conjugated nitroalkenes follows the expected pathway to furnish naphthoquinones in moderate yields. However, a strategic variation of this reaction by employing nitroalkenes bearing an additional nucleophilic site results in [4+4] annulation leading to complex fused and spiro heterocycles in high yields with high selectivity through a cascade
Efficient organocatalytic asymmetric synthesis of 2-amino-4H-chromene-3-carbonitrile derivatives
作者:Yu Gao、Wen Yang、Da-Ming Du
DOI:10.1016/j.tetasy.2012.02.019
日期:2012.3
enantioselective tandem Michael addition–cyclization of malononitrile to nitroalkenes for the direct synthesis of chiral 2-amino-4H-chromene-3-carbonitrile derivatives was investigated. Good yields and enantioselectivities (up to 91% ee) were achieved. This organocatalytic asymmetric tandem Michael addition–cyclization provides an efficient routetoward the synthesis of optically active functionalized chromenes
The efficient simultaneous activation of cyclohexenones or simple alkyl acyclic enones and 2‐hydroxynitrostyrenes was realized by using a prolinolthioethercatalyst. Thus, a highly chemo‐, diastereo‐ and enantioselective synthesis of functionalized tetrahydroxanthenones and chromanes with up to three contiguous stereocenters was developed.
A catalytic asymmetric method for the synthesis of polysubstituted chromans via an oxa-Michael-nitro-Michael reaction has been developed. The squaramide-catalyzed domino reaction of 2-hydroxynitrostyrenes with trans-β-nitroolefins produced chiral chromans with excellent enantioselectivities (up to 99% ee), diastereoselectivities (up to >20 : 1 dr), and moderate to good yields (up to 82%).