| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1347645 | Tetrahedron: Asymmetry | 2008 | 8 Pages |
Chlorosulfonyl isocyanate addition to (−)- and (+)-apopinene furnished monoterpene-fused β-lactams in highly regio- and stereospecific reactions. β-Lactams 5 and 13 exhibited reactivities similar to those of the cycloalkane-fused analogs and were easily converted to the β-amino acid and its protected derivatives. The base-catalyzed isomerization of the cis-amino ester afforded the corresponding trans-amino acid enantiomers in excellent yields. The complete isomerization is explained by the stability difference, which was estimated by ab initio calculations between the cis- and trans-diastereomers.
Graphical abstractChlorosulfonyl isocyanate addition to (−)- and (+)-apopinene furnished monoterpene-fused β-lactams in highly regio- and stereospecific reactions, which were easily converted to β-amino acids and their protected derivatives. The base-catalyzed isomerization of the cis-amino ester afforded the corresponding trans-amino acid enantiomers in excellent yields.Figure optionsDownload full-size imageDownload as PowerPoint slide
(1R,2R,5S,7R)-8,8-Dimethyl-3-azatricyclo[5.1.1.02,5]nonan-4-oneC10H15NO[α]D20=-80.0 (c 0.5, MeOH)Source of chirality: (1R)-(−)-myrtenalAbsolute configuration: (1R,2R,5S,7R)
Methyl (1R,2R,3S,5R)-2-amino-6,6-dimethylbicyclo[3.1.1]heptane-3-carboxylate hydrochlorideC11H20ClNO2[α]D20=+4.8 (c 0.5, MeOH)Source of chirality: (1R)-(−)-myrtenalAbsolute configuration: (1R,2R,3S,5R)
Ethyl (1R,2R,3S,5R)-2-amino-6,6-dimethylbicyclo[3.1.1]heptane-3-carboxylate hydrochlorideC12H22ClNO2[α]D20=+23 (c 0.5, MeOH)Source of chirality: (1R)-(−)-myrtenalAbsolute configuration: (1R,2R,3S,5R)
(1R,2R,3S,5R)-2-Amino-6,6-dimethylbicyclo[3.1.1]heptane-3-carboxylic acid hydrochlorideC10H18ClNO2[α]D20=+22.5 (c 0.5, MeOH)Source of chirality: (1R)-(−)-myrtenalAbsolute configuration: (1R,2R,3S,5R)
(1R,2R,3S,5R)-2-Amino-6,6-dimethylbicyclo[3.1.1]heptane-3-carboxylic acidC10H17NO2[α]D20=-1.6 (c 0.5, MeOH)Source of chirality: (1R)-(−)-myrtenalAbsolute configuration: (1R,2R,3S,5R)
(1R,2R,5S,7R)-N-tert-Butoxycarbonyl-8,8-dimethyl-3-azatricyclo[5.1.1.02,5]nonan-4-oneC15H23NO3[α]D20=-41.1 (c 0.5, MeOH)Source of chirality: (1R)-(−)-myrtenalAbsolute configuration: (1R,2R,5S,7R)
(1R,2R,3S,5R)-(2-tert-Butoxycarbonylamino)-6,6-dimethylbicyclo[3.1.1]heptane-3-carboxylic acidC15H25NO4[α]D20=+4.6 (c 0.5, MeOH)Source of chirality: (1R)-(−)-myrtenalAbsolute configuration: (1R,2R,3S,5R)
(1R,2R,3S,5R)-2-(9H-Fluoren-9-yl-methoxycarbonylamino)-6,6-dimethylbicyclo[3.1.1]heptane-3-carboxylic acidC13H23NO2[α]D20=+2 (c 0.25, MeOH)Source of chirality: (1R)-(−)-myrtenalAbsolute configuration: (1R,2R,3S,5R)
(1S,2S,3R,5S)-2-Dimethylamino-6,6-dimethylbicyclo[3.1.1]heptane-3-carboxylic acid hydrochlorideC12H22ClNO2[α]D20=+10.7 (c 0.505, MeOH)Source of chirality: (1R)-(−)-myrtenalAbsolute configuration: (1S,2S,3R,5S)
Ethyl (1R,2R,3R,5R)-2-amino-6,6-dimethylbicyclo[3.1.1]heptane-3-carboxylate hydrochlorideC12H22ClNO2[α]D20=-32.4 (c 0.5, MeOH)Source of chirality: (1R)-(−)-myrtenalAbsolute configuration: (1R,2R,3R,5R)
(1R,2R,3R,5R)-2-Amino-6,6-dimethylbicyclo[3.1.1]heptane-3-carboxylic acidC10H17NO21[α]D20=-42.7 (c 0.5, MeOH)Source of chirality: (1R)-(−)-myrtenalAbsolute configuration: (1R,2R,3R,5R)
(1R,2R,3R,5R)-2-Amino-6,6-dimethylbicyclo[3.1.1]heptane-3-carboxylic acid hydrochlorideC10H18ClNO2[α]D20=-32.6 (c 0.5, MeOH)Source of chirality: (1R)-(−)-myrtenalAbsolute configuration: (1R,2R,3R,5R)
(1R,2R,3R,5R)-(2-tert-Butoxycarbonylamino)-6,6-dimethylbicyclo[3.1.1]heptane-3-carboxylic acidC15H25NO4[α]D20=-43.3 (c 0.5, MeOH)Source of chirality: (1R)-(−)-myrtenalAbsolute configuration: (1R,2R,3R,5R)
(1R,2R,3R,5R)-2-(9H-Fluoren-9-yl-methoxycarbonylamino)-6,6-dimethylbicyclo[3.1.1]heptane-3-carboxylic acidC25H27NO4[α]D20=-4 (c 0.25, MeOH)Source of chirality: (1R)-(−)-myrtenalAbsolute configuration: (1R,2R,3R,5R)
Ethyl (2S,1′R,2′R,3′S,5′R)-2-[(2′-tert-butoxycarbonylamino)-6′,6′-dimethylbicyclo[3.1.1]heptane-3′-carbonyl)]amino-3-phenylpropionateC26H38N2O5[α]D20=+22.5 (c 0.5, MeOH)Source of chirality: (1R)-(−)-myrtenal, (S)-phenylalanineAbsolute configuration: (2S,1′R,2′R,3′S,5′R)
Ethyl (2S,1′R,2′R,3′R,5′R)-2-[[(2′-tert-butoxycarbonylamino)-6′,6′-dimethylbicyclo[3.1.1]heptane-3′-carbonyl)]amino]-3-phenylpropionateC26H38N2O5[α]D20=-15 (c 0.25, MeOH)Source of chirality: (1R)-(−)-myrtenal, (S)-phenylalanineAbsolute configuration: (2S,1′R,2′R,3′R,5′R)
Ethyl (2S,1′S,2′S,3′R,5′S)-2-[(2′-tert-butoxycarbonylamino)-6′,6′-dimethylbicyclo[3.1.1]heptane-3′-carbonyl)]amino-3-phenylpropionateC26H38N2O5[α]D20=-10 (c 0.25, MeOH)Source of chirality: (1R)-(−)-myrtenal, (S)-phenylalanineAbsolute configuration: (2S,1′S,2′S,3′R,5′S)
Ethyl (2S,1′S,2′S,3′S,5′S)-2-[[(2′-tert-butoxycarbonylamino)-6′,6′-dimethylbicyclo[3.1.1]heptane-3′-carbonyl)]amino]-3-phenylpropionateC26H38N2O5[α]D20=+18 (c 0.25, MeOH)Source of chirality: (1R)-(−)-myrtenal, (S)-phenylalanineAbsolute configuration: (2S,1′S,2′S,3′S,5′S)
