Synthesis of unsaturated silyl nitronates via the silylation of conjugated nitroalkenes
作者:Elizaveta A. Khotyantseva、Andrey A. Tabolin、Roman A. Novikov、Yulia V. Nelyubina、Sema L. Ioffe
DOI:10.1016/j.tetlet.2018.07.011
日期:2018.8
A new method for the synthesis of conjugated silyl nitronates from nitroalkenes is described. The procedure has wide substrate scope and is compatible with in situ generation of the substrates from 2-nitroalcohols or 2-chloro-nitroalkanes. A cascade transformation to give 3,4,5,6-tetrahydropyridine N-oxide derivatives was disclosed.
The morpholino enamine of monoprotected butane-2,3-dione reacts with cyclic and acyclic conjugated nitroalkenes in a Michael-type reaction to yield nitro-substituted α-diketones, after acidic hydrolysis of the mononitroalkylated enamine adducts. Cyclopentanone, hexahydro-1H-pentalen-2-one and octahydro-2H-inden-2-one derivatives are readily obtained by base-catalyzed intramolecular nitroaldol reaction of the acyclic hydrolysis products.
have been shown to promote highly diastereoselective and complementary enantioselective formal [3 + 2]carbocyclization reactionsbetween 2,3‐butanedione and conjugated nitroalkenes with formation of enantiomerically rich 2‐hydroxy‐3‐nitrocyclopentanone derivatives. The reactions were carried out both in solvent and under solvent‐free conditions. The absolute configurations of the products were assigned