| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1350553 | Tetrahedron: Asymmetry | 2007 | 8 Pages |
A facile method for the preparation of tert-butyl (3R,5S)-6-hydroxy-3,5-O-isopropylidene-3,5-dihydroxyhexanoate is described by a chemoenzymatic approach. In this method, one hydroxyl stereocenter at C5 is obtained with a high ee value (up to 98.0%) via an enzymatic transesterification resolution of l-chloro-3-(4-methylbenzyloxy)-2-propanol. The other hydroxyl stereocenter at C3 was built with 98.0% de, by acid-hydrolysis of a 1,3-diol-acetonide syn/anti-10. It is noteworthy that the reduction of β-hydroxy ketone 8 with sodium borohydride can be carried out smoothly in aqueous isopropyl alcohol with a high diastereomeric ratio syn/anti (drs:a) of 4.0:1.
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(R)-l-Chloro-3-benzyloxy-2-propanolC10H13ClO2Ee = 97.3% [by chiral HPLC][α]D20=+1.5 (c 3.3, CHCl3)Source of chirality: enzymatic resolutionAbsolute configuration: (2R)
(R)-1-Chloro-3-(2,4-dichlorobenzyloxy)-2-propanolC10H11Cl3O2Ee = 96.8% [by chiral HPLC][α]D20=+2.2 (c 3.4, CHCl3)Source of chirality: enzymatic resolutionAbsolute configuration: (2R)
(R)-1-Chloro-3-(4-methyoxybenzyloxy)-2-propanolC10H15ClO3Ee = 98.2% [by chiral HPLC][α]D20=+1.9 (c 3.9, CHCl3)Source of chirality: enzymatic resolutionAbsolute configuration: (2R)
(R)-1-Chloro-3-(4-fluorobenzyloxy)-2-propanolC10H12ClFO2Ee = 98.1% [by chiral HPLC][α]D20=+2.4 (c 1.8, CHCl3)Source of chirality: enzymatic resolutionAbsolute configuration: (2R)
(R)-1-Chloro-3-(4-chlorobenzyloxy)-2-propanolC10H12Cl2O2Ee = 96.7% [by chiral HPLC][α]D20=+2.2 (c 3.2, CHCl3)Source of chirality: enzymatic resolutionAbsolute configuration: (2R)
(R)-l-Chloro-3-(4-methylbenzyloxy)-2-propanolC11H15ClO2Ee = 98.0% [by chiral HPLC][α]D20=+2.0 (c 3.5, CHCl3)Source of chirality: enzymatic resolutionAbsolute configuration: (2R)
(S)-2-Acetoxy-1-chloro-3-benzyloxy-2-propanolC12H15ClO3Ee = 88.5% [by chiral HPLC][α]D20=+7.3 (c 3.3, CHCl3)Source of chirality: enzymatic resolutionAbsolute configuration: (2S)
(S)-2-Acetoxy-1-chloro-3-(2,4-dichlorobenzyloxy)-2-propanolC12H13Cl3O2Ee = 84.5% [by chiral HPLC][α]D20=+6.8 (c 3.4, CHCl3)Source of chirality: enzymatic resolutionAbsolute configuration: (2S)
(S)-2-Acetoxy-1-chloro-3-(4-methyoxybenzyloxy)-2-propanolC13H17ClO4Ee = 90.1% [by chiral HPLC][α]D20=+8.8 (c 3.5, CHCl3)Source of chirality: enzymatic resolutionAbsolute configuration: (2S)
(S)-2-Acetoxy-1-chloro-3-(4-fluorobenzyloxy)-2-propanolC12H14ClFO5Ee = 91.5% [by chiral HPLC][α]D20=+8.4 (c 3.7, CHCl3)Source of chirality: enzymatic resolutionAbsolute configuration: (2S)
(S)-2-Acetoxy-1-chloro-3-(4-chlorobenzyloxy)-2-propanolC12H14Cl2O2Ee = 96.0% [by chiral HPLC][α]D20=+8.9 (c 3.1, CHCl3)Source of chirality: enzymatic resolutionAbsolute configuration: (2S)
(S)-2-Acetoxy-l-chloro-3-(4-methylbenzyloxy)-2-propanolC13H17ClO5Ee = 96.0%[by chiral HPLC][α]D20=+8.7 (c 2.2, CHCl3)Source of chirality: enzymatic resolutionAbsolute configuration: (2S)
tert-Butyl (S)-6-(4-methybenzyloxy)-5-hydroxy-3-oxohexanoateC18H26O5Ee = 98.0% [by chiral HPLC][α]D20=-13.0 (c 2.5, CHCl3)Source of chirality: enzymatic resolutionAbsolute configuration: (5S)
tert-Butyl (3R,5S)-6-(4-methybenzyloxy)-3,5-O-isopropylidene-3,5-dihydroxyhexanoateC21H32O5De = 98.0% [by GC][α]D20=-6.5 (c 2.0, CHCl3)Source of chirality: enzymatic resolution and chemical resolutionAbsolute configuration: (3R,5S)
tert-Butyl (3R,5S)-6-hydroxy-3,5-O-isopropylidene-3,5-dihydroxyhexanoateC13H24O5De = 98.0% [by GC][α]D20=+9.9 (c 2.0, CHCl3)Source of chirality: enzymatic resolution and chemical resolutionAbsolute configuration: (3R,5S)
