| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1345348 | Tetrahedron: Asymmetry | 2014 | 8 Pages |
The enantioselective tandem Michael addition reaction of dimedone and related 1,3-dicarbonyl compounds with α,β-unsaturated N-acylated succinimides catalyzed by a chiral squaramide catalyst has been investigated. This reaction provides a new approach for the synthesis of chiral enol lactones in good yields with moderate to high enantioselectivities (up to 88% ee) through the enantioselective Michael addition followed by lactonization and removal of the succinimide auxiliary.
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(R)-7,7-Dimethyl-4-phenyl-4,6,7,8-tetrahydro-3H-chromene-2,5-dioneC17H18O3ee = 85%[α]D25=-98.8 (c 2.14, CH2Cl2)Source of chirality: Asymmetric synthesisAbsolute configuration: (R)
(S)-4-(2-Chlorophenyl)-7,7-dimethyl-4,6,7,8-tetrahydro-3H-chromene-2,5-dioneC17H17ClO3ee = 54%[α]D25=-36.5 (c 0.48, CH2Cl2)Source of chirality: Asymmetric synthesisAbsolute configuration: (S)
(R)-4-(4-Bromophenyl)-7,7-dimethyl-4,6,7,8-tetrahydro-3H-chromene-2,5-dioneC17H17BrO3ee = 88%[α]D25=-27.7 (c 1.43, CH2Cl2)Source of chirality: Asymmetric synthesisAbsolute configuration: (R)
(R)-4-(4-Methoxyphenyl)-7,7-dimethyl-4,6,7,8-tetrahydro-3H-chromene-2,5-dioneC18H20O4ee = 85%[α]D25=-76.9 (c 2.04, CH2Cl2)Source of chirality: Asymmetric synthesisAbsolute configuration: (R)
(R)-7,7-Dimethyl-4-(4-nitrophenyl)-4,6,7,8-tetrahydro-3H-chromene-2,5-dioneC17H17NO5ee = 70%[α]D25=-92.4 (c 1.50, CH2Cl2)Source of chirality: Asymmetric synthesisAbsolute configuration: (R)
(R)-7,7-Dimethyl-4-(p-tolyl)-4,6,7,8-tetrahydro-3H-chromene-2,5-dioneC18H20O3ee = 80%[α]D25=-82.1 (c 1.03, CH2Cl2)Source of chirality: Asymmetric synthesisAbsolute configuration: (R)
(S)-7,7-Dimethyl-4-(furan-2-yl)-4,6,7,8-tetrahydro-3H-chromene-2,5-dioneC15H16O4ee = 88%[α]D25=-24.8 (c 0.99, CH2Cl2)Source of chirality: Asymmetric synthesisAbsolute configuration: (S)
(S)-4,7,7-Trimethyl-4,6,7,8-tetrahydro-3H-chromene-2,5-dioneC12H16O3ee = 77%[α]D25=-5.0 (c 2.09, CH2Cl2)Source of chirality: Asymmetric synthesisAbsolute configuration: (S)
(S)-4-Ethyl-7,7-dimethyl-4,6,7,8-tetrahydro-2H-chromene-2,5-dioneC13H18O3ee = 69%[α]D25=+4.6 (c 1.14, CH2Cl2)Source of chirality: Asymmetric synthesisAbsolute configuration: (S)
(S)-7,7-Dimethyl-4-propyl-4,6,7,8-tetrahydro-3H-chromene-2,5-dioneC14H20O3ee = 72%[α]D25=+1.7 (c 1.83, CH2Cl2)Source of chirality: Asymmetric synthesisAbsolute configuration: (S)
(R)-4-Phenyl-4,6,7,8-tetrahydro-3H-chromene-2,5-dioneC15H14O3ee = 72%[α]D25=+80.8 (c 1.54, CH2Cl2)Source of chirality: Asymmetric synthesisAbsolute configuration: (R)
(S)-4-Methyl-4,6,7,8-tetrahydro-3H-chromene-2,5-dioneC10H12O3ee = 60%[α]D25=-7.0 (c 1.36, CH2Cl2)Source of chirality: Asymmetric synthesisAbsolute configuration: (S)
(R)-4-Phenyl-3,4-dihydropyrano[3,2-c]chromene-2,5-dioneC18H12O4ee = 23%[α]D25=-23.5 (c 2.15, CH2Cl2)Source of chirality: Asymmetric synthesisAbsolute configuration: (R)
(S)-4-Methyl-3,4-dihydropyrano[3,2-c]chromene-2,5-dioneC13H10O4ee = 50%[α]D28=-19.2 (c 2.02, CH2Cl2)Source of chirality: Asymmetric synthesisAbsolute configuration: (S)
(R)-7-Methyl-4-(p-tolyl)-3,4-dihydropyrano[4,3-b]pyran-2,5-dioneC16H14O4ee = 19%[α]D25=+9.1 (c 1.77, CH2Cl2)Source of chirality: Asymmetric synthesisAbsolute configuration: (R)
(S)-4,7-Dimethyl-3,4-dihydropyrano[4,3-b]pyran-2,5-dioneC10H10O4ee = 46%[α]D25=+8.1 (c 0.15, CH2Cl2)Source of chirality: Asymmetric synthesisAbsolute configuration: (S)
(R)-5-Acetyl-3,4-dihydro-6-methyl-4-phenylpyran-2-oneC14H14O3ee = 29%[α]D25=-89.1 (c 0.18, CH2Cl2)Source of chirality: Asymmetric synthesisAbsolute configuration: (R)
3-(((S)-((1S,2S,4S,5R)-5-Ethylquinuclidin-2-yl)(6-methoxyquinolin-4-yl)methyl)amino)-4-((4-(trifluoromethyl)phenyl)amino)cyclobut-3-ene-1,2-dioneC31H31F3N4O3ee = 46%[α]D25=-72.7 (c 0.30, DMSO)Source of chirality: Asymmetric synthesisAbsolute configuration: (S) (S,S,S,R)
