Conjugated nitroalkenes: versatile intermediates in organic synthesis

Magnetically Separable Base Catalysts: Heterogeneous Catalysis vs. Quasi-Homogeneous Catalysis

“…The condensations of activated methylene groups with aldehydes, in particular Knoevenagel [36] and nitroaldol [37] condensations, are efficient carbon-carbon bond forming reactions. These reactions are utilized widely in the synthesis of valuable organic compounds that are of importance to different biological and pharmaceutical applications.…”

Asymmetric catalysis with bifunctional cinchona alkaloid-based urea and thiourea organocatalysts

“…Nitro-groups possess two co-planar Lewis-basic oxygen atoms capable of accepting two hydrogen bonds 11b from (thio)urea derivatives and the enantioenriched nitroalkane adducts derived from the asymmetric addition of pronucleophiles to nitroalkenes are highly pliable synthetically. 24,25 Scheidt and co-workers 26 discovered a method for synthesising an adduct formally derived from a Stetter-type addition of an acyl anion equivalent to a nitroolefin. Treatment of a mixture of nitroalkene 27 and thiazolium ion 28 in the presence of a fluoride ion source and stoichiometric amounts of 18 resulted in the formation of b-nitroketone 29 with good levels of enantioselectivity (Scheme 5).…”

An efficient synthesis of 3-substituted indole derivates under ultrasound irradiation

“…5,135.4,132.6,131.7,128.6,126.9,121.4,119.8,118.6,115.6,110.7,109.2,78.9,39.8, (d,J = 8.0 Hz,1H),7.30 (d,J = 7.7 Hz,1H),7.27 (d,J = 8.7 Hz,1H),2H),7.04 (dd,J = 7.5 Hz,1H),6.90 (dd,J = 7.6 Hz,1H),6.76 (d,J = 8.0 Hz,1H),5.39 (dd,J = 9.1,6.7 Hz,1H),5.29 (dd,J = 12.5,6.4 Hz,1H),2H), 2.42 (s, 3H).…”

“…The conjugate addition of indoles to Michael acceptors provides easy access to 3-substituted indole derivates [4], which are important building blocks for the synthesis of biologically important compounds. Among various types of Michael acceptors, nitroalkenes are undoubtedly the strongest and particularly versatile one [5], since the nitro group is a powerful electron-withdrawing substituent and it may be transformed into a legion of diverse functionality [6]. Although it was reported by Noland and co-workers firstly in 1950s [7], the conjugate addition of indoles to nitroalkenes has received relatively less attention than others.…”