New bifunctional 1,3-diamine organocatalysts derived from (+)-camphoric acid for asymmetric Michael addition of 1,3-dicarbonyl compounds to nitroolefins
Novel 1,3-diamine-derived bifunctional thiourea and squaramide organocatalysts were synthesized from (+)-camphoric acid. These catalysts were easily obtained in up to two to five synthetic steps, in a flexible approach that facilitates their structure variation. Their catalytic activity was examined in the asymmetric Michael addition of 1,3-dicarbonyl compounds to several trans-β-nitrostyrenes. Yields up to 98% and enantiomeric excesses up to 74% and high diastereoselectivities when applicable (dr up to 93:7) were obtained in these reactions showing that 1,3-diamine-derived bifunctional thioureas are efficient organocatalysts.
Murtinho, Dina,Rénio, Márcia,Ventura, M. Rita
(2022/02/19)
Simple primary β-amino alcohols as organocatalysts for the asymmetric Michael addition of β-keto esters to nitroalkenes
Simple primary β-amino alcohols act as an efficient organocatalysts in the asymmetric Michael addition of β-keto esters with nitroalkenes affording highly pure chiral Michael adducts. Also, both enantiomers of the adducts were obtained, depending on the specific catalyst used and reaction temperature.
Recyclable Chiral Bifunctional Thioureas Derived from [60]Fullerene and Their Use as Highly Efficient Organocatalysts for the Asymmetric Nitro-Michael Reaction
Three novel fullerothioureas derived from natural valine, phenylalanine, and tert-leucine have been prepared by Prato's reaction of [60]fullerene and the corresponding aldehydes. These hybrids have been used as organocatalysts in a typical stereoselective
Andrés, José M.,González, Miguel,Maestro, Alicia,Naharro, Daniel,Pedrosa, Rafael
p. 2683 - 2691
(2017/05/29)
Supported bifunctional thioureas as recoverable and reusable catalysts for enantioselective nitro-Michael reactions
The catalytic activity of different supported bifunctional thioureas on sulfonylpolystyrene resins has been studied in the nitro-Michael addition of different nucleophiles to trans-β-nitrostyrene derivatives. The activity of the catalysts depends on the l
Andrés, José M.,Ceballos, Miriam,Maestro, Alicia,Sanz, Isabel,Pedrosa, Rafael
p. 628 - 635
(2016/07/06)
Bottom-up synthesis of supported thioureas and their use in enantioselective solvent-free aza-Henry and Michael additions
Two sets of supported chiral thioureas, which differ in the length of the tether that connects the chiral appendage to the polymer structure and the effective functionalization, have been prepared by copolymerization of styrene, novel styryl thioureas der
Andrs, Jos M.,De La Cruz, Noelia,Valle, Mara,Pedrosa, Rafael
p. 86 - 92
(2016/02/05)
New class of bifunctional thioureas from l-proline: Highly enantioselective Michael addition of 1,3-dicarbonyls to nitroolefins
A new class of bifunctional tertiary amine thiourea was synthesized from l-proline. The reported thiourea is amenable to steric and electronic modifications at the stereogenic center bearing a thiourea moiety. Excellent enantioselectivity was obtained in the Michael addition of 2,4-pentanedione to various nitro olefins using the new organocatalyst. The construction of contiguous stereocenters via the Michael reaction of substituted 1,3-dicarbonyls to nitro olefins was also carried out with very good yield, enantioselectivity, and diastereoselectivity.
Novel chiral hydrogen bond donor catalysts based on a 4,5-diaminoxanthene scaffold: Application to enantioselective conjugate addition of 1,3-dicarbonyl compounds to nitroalkenes
Novel chiral hydrogen bond donor catalysts based on a 4,5-diamino-9, 9′-dimethylxanthene skeleton were designed and synthesized. Among the phenylurea-amide hybrid molecules prepared from various natural/unnatural chiral amino acids, the phenylalanine-deri
Ephedrine- and pseudoephedrine-derived thioureas in asymmetric michael additions of keto esters and diketones to nitroalkenes
Ephedrine-derived bifunctional thioureas have been synthesized and applied as organocatalysts in Michael additions of 1,3-dicarbonyl compounds to nitroalkenes. Georg Thieme Verlag Stuttgart.
Flock, Angelika Marie,Krebs, Anke,Bolm, Carsten
supporting information; experimental part
p. 1219 - 1222
(2010/08/20)
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