Lipase-catalyzed enantiomeric separation of 1-aryloxy-3-thiocyanatopropan-2-ols: an attempt to prepare optically active thiiranes

Opening of the epoxide ring of several arylglycidyl ethers with thiocyanato anion followed by acetylation yielded racemic mixtures of 1-aryloxy-3-thiocyanato-propan-2-yl acetates. A lipase-catalyzed hydrolysis of the acetates resulted in the separation of the enantiomers. The unstable, optically active (S)-1-aryloxy-3-thiocyanatopropan-2-ols, were converted into the corresponding 2-aryloxymethyl thiiranes, which instantly polymerized to yield the optically active oligomers.

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(S)-(+)-1-Phenoxy-3-thiocyanatopropan-2-olC10H11NSO2Ee = 88%[α]D20=+5.6 (c 1.96, CHCl3)Source of chirality: enzymatic kinetic resolutionAbsolute configuration: S

(S)-(+)-1-(2,4-Dichlorophenoxy)-3-thiocyanatopropan-2-olC10H9Cl2NSO2Ee >99%[α]D20=+0.7 (c 8.82, CHCl3)Source of chirality: enzymatic kinetic resolutionAbsolute configuration: S

(S)-(+)-Thiocyanato-3-(p-tolyloxy)propan-2-olC11H13NSO2Ee = 95%[α]D20=+1.9 (c 1.80, CHCl3)Source of chirality: enzymatic kinetic resolutionAbsolute configuration: S

(S)-(+)-1-(4-Chlorophenoxy)-3-thiocyanatopropan-2-olC10H10NClSO2Ee >99%[α]D20=+0.45 (c 4.50, CHCl3)Source of chirality: enzymatic kinetic resolutionAbsolute configuration: S

(R)-(−)-1-Phenoxy-3-thiocyanatopropan-2-yl acetateC12H13NSO3Ee = 99%[α]D20=-50.75 (c 2, CHCl3)Source of chirality: enzymatic kinetic resolutionAbsolute configuration: R

(R)-(−)-1-(2,4-Dichlorophenoxy)-3-thiocyanatopropan-2-yl acetateC12H11NCl2SO3Ee >99%[α]D20=+22.4 (c 5, CHCl3)Source of chirality: enzymatic kinetic resolutionAbsolute configuration: R

(R)-(−)-3-Thiocyanato-1-(p-tolyloxy)propan-2-yl acetateC13H15NSO3Ee = 61%[α]D20=-45 (c 2, CHCl3)Source of chirality: enzymatic kinetic resolutionAbsolute configuration: R

(R)-(−)-1-(4-Chlorophenoxy)-3-thiocyanatopropan-2-yl acetateC12H12NClSO3Ee = 90%[α]D20=-37.5 (c 2, CHCl3)Source of chirality: enzymatic kinetic resolutionAbsolute configuration: R