A general synthesis of a new type of heterodiene, the N-vinyl nitrone, is described. The synthetic sequence begins with the conjugate addition of benzeneselenol to nitroalkenes (in turn derived from Henry reaction of an aldehyde and a nitroalkane) to provide 2-selenenylnitroalkenes. These selenonitroalkanes are reduced to the corresponding hydroxylamines which are combined with aldehydes to form nitrones
A facile and convenient synthesis of acetic nitronic anhydrides from aliphatic nitroalkenes and lithium ketone enolates and the efficient conversion of these anhydrides to 1,4-diketones, alkylpyrroles, diketone monooximes, dihydro-1,2-oxazines, pyrrolidines, 2-hydroxypyrrolidines, and 1-pyrrolines are recorded.
Zn-Catalyzed Enantio- and Diastereoselective Formal [4 + 2] Cycloaddition Involving Two Electron-Deficient Partners: Asymmetric Synthesis of Piperidines from 1-Azadienes and Nitro-Alkenes
作者:John C. K. Chu、Derek M. Dalton、Tomislav Rovis
DOI:10.1021/jacs.5b00033
日期:2015.4.8
We report a catalytic asymmetricsynthesis of piperidines through [4 + 2] cycloaddition of 1-azadienes and nitro-alkenes. The reaction uses earth abundant Zn as catalyst and is highly diastereo- and regioselective. A novel BOPA ligand (F-BOPA) confers high reactivity and enantioselectivity in the process. The presence of ortho substitution on the arenes adjacent to the bis(oxazolines) was found to
A series of α-substituted nitroolefins were employed in organocatalytic asymmetric Michael reactions with aldehydes. γ-Nitro carbonyl products were achieved in good yields (up to 86%) with good stereoselectivities (up to 96% ee and 24â:â1 dr). Reduction of the nitro group followed by intramolecular reductive amination successfully afforded various novel optically active 2,4-disubstituted pyrrolidine compounds.
Organocatalytic Enantioselective Michael‐Aldol[3+2] Annulation for the Synthesis of Nitro‐Methanobenzo[7] annulenes
作者:Yang Zhang、Jin‐Yu Liu、Xiao‐Hai Zhang
DOI:10.1002/ejoc.202100974
日期:2021.9.21
An enantioselective Michael-Aldol[3+2] annulation via bifunctional thiourea catalysis has been reported, and a series of nitro-methanobenzo[7]annulenes with potential biological activities were synthesized in good yields with excellent enantio- and diastereoselectivities.