| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1347064 | Tetrahedron: Asymmetry | 2009 | 11 Pages |
A study of copper-phosphoramidite-catalysed ZnR2 and AlR3 additions to 1,1′-dicarbonyl-activated cyclic Michael acceptors has revealed high enantioselectivities for AlR3 (R = Me, Et) 1,4-addition to a range of 3-acylcoumarins (85–98% ee, trans:cis ∼90:10) using commercial or readily available ligands. Large substituents at the 6-position, and to some extent at the 5-position, of the coumarin are less well tolerated, nor is truncation of the coumarin motif to a comparable 2-acylcyclohexenone (ee values up to 78%).
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide
(3R,4S)-3-Benzoyl-4-ethylchroman-2-oneC17H14O3Ee = 88%[α]D25=-35.7 (c 1.00, CHCl3)Source of chirality: asymmetric catalysisAbsolute configuration: (3R,4S)
(3R,4S)-3-Benzoyl-4-ethylchroman-2-oneC18H16O3Ee = 96%[α]D25=+83.8 (c 1.00, CHCl3)Source of chirality: asymmetric catalysisAbsolute configuration: (3R,4S)
(3R,4S)-3-Benzoyl-8-bromo-4-methylchroman-2-oneC17H13BrO3Ee = 88%[α]D25=-9.3 (c 1.00, CHCl3)Source of chirality: asymmetric catalysisAbsolute configuration: (3R,4S)
(3R,4S)-3-Benzoyl-8-bromo-4-ethylchroman-2-oneC18H15BrO3Ee = 96%[α]D25=+90.7 (c 0.5, CHCl3)Source of chirality: asymmetric catalysisAbsolute configuration: (3R,4S)
(3R,4S)-3-Benzoyl-8-methoxy-4-methylchroman-2-oneC18H16O4Ee = 87%[α]D25=-27.0 (c 1.00, CHCl3)Source of chirality: Asymmetric catalysisAbsolute configuration: (3R,4S)
(3R,4S)-3-Benzoyl-8-methoxy-4-methylchroman-2-oneC18H16O4Ee = 96%[α]D25=+32.2 (c 1.0, CHCl3)Source of chirality: asymmetric catalysisAbsolute configuration: (3R,4S)
(3R,4S)-3-Benzoyl-4-isobutyl-8-methoxychroman-2-oneC21H22O4Ee = 75%[α]D25=+7.3 (c 1.00, CHCl3)Source of chirality: asymmetric catalysisAbsolute configuration: (3R,4S)
(3R,4S)-3-Benzoyl-4-ethyl-7-methoxychroman-2-oneC19H18O4Ee = 98%[α]D25=+56.8 (c 1.00, CHCl3)Source of chirality: asymmetric catalysisAbsolute configuration: (3R,4S)
(3R,4S)-3-Benzoyl-6-methoxy-4-methylchroman-2-oneC18H16O4Ee = 37%[α]D25=-13.1 (c 1.00, CHCl3)Source of chirality: asymmetric catalysisAbsolute configuration: (3R,4S)
(3R,4S)-3-Benzoyl-4-ethyl-6-methoxychroman-2-oneC19H18O4Ee = 48%[α]D25=+1.0 (c 1.00, CHCl3)Source of chirality: asymmetric catalysisAbsolute configuration: (3R,4S)
(3R,4S)-3-Benzoyl-4,6-dimethylchroman-2-oneC18H16O3Ee = 67%[α]D25=-43.9 (c 1.00, CHCl3)Source of chirality: asymmetric catalysisAbsolute configuration: (3R,4S)
(3R,4S)-3-Benzoyl-4-ethyl-6-methylchroman-2-oneC19H18O3Ee = 85%[α]D25=+46.4 (c 1.00, CHCl3)Source of chirality: asymmetric catalysisAbsolute configuration: (3R,4S)
(1R,2S)-2-Benzoyl-1-ethyl-1,2-dihydro-benzo[f]chromen-3-oneC22H18O3Ee = 90%[α]D25=-38.1 (c 1.00, CHCl3)Source of chirality: asymmetric catalysisAbsolute configuration: (1R,2S)
(3S,4R)-Ethyl-4-methyl-2-oxochroman-3-carboxylateC13H14O4Ee = 53%[α]D25=+13.8 (c 1.00, CHCl3)Source of chirality: asymmetric catalysisAbsolute configuration: (3S,4R)
(3R,4S)-Ethyl-4-ethyl-2-oxochroman-3-carboxylateC14H16O4Ee = 90%[α]D25=+19.4 (c 1.00, CHCl3)Source of chirality: asymmetric catalysisAbsolute configuration: (3R,4S)
