Asymmetric synthesis of (−)-α-conhydrine

The enantioselective synthesis of (−)-α-conhydrine has been achieved by two different synthetic routes. The key steps include Sharpless asymmetric dihydroxylation, regioselective opening of a cyclic sulfate and Wittig olefination.

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Methyl (2S,3S)-2,3-dihydroxypentanoateC6H12O4[α]D25=-5.5 (c 1.0, CHCl3)Source of chirality: asymmetric dihydroxylationAbsolute configuration: (2S,3S)

(2S,3S)-5-Ethyl-2,2-dioxo-[1,3,2]dioxathiolane-4-carboxylic acid methyl esterC6H10SO6[α]D25=-15.6 (c 1, CHCl3)Source of chirality: asymmetric dihydroxylationAbsolute configuration: (2S,3S)

Methyl (2R,3S)-2-azido-3-hydroxypentanoateC6H11N3O3[α]D25=-4.7 (c 1.2, CHCl3)Source of chirality: asymmetric dihydroxylationAbsolute configuration: (2R,3S)

Methyl (2R,3S)-2-tert-butoxycarbonylamino-3-hydroxypentanoateC11H21NO5[α]D25=-6.9 (c 2.0, CHCl3)Source of chirality: asymmetric dihydroxylationAbsolute configuration: (2R,3S)

[5-Hydroxy-1-(1-hydroxypropyl)-pent-2-enyl]-carbamic acid tert-butyl esterC13H25NO4[α]D25=-10.3 (c 1, CHCl3)Source of chirality: asymmetric dihydroxylationAbsolute configuration: (5R,6S)

[5-Hydroxy-1-(1-hydroxypropyl)-pentyl]-carbamic acid tert-butyl esterC13H27NO4[α]D25=-9.8 (c 1, CHCl3)Source of chirality: asymmetric dihydroxylationAbsolute configuration: (5R,6S)

2-(1-Hydroxypropyl)-piperidine-1-carboxylic acid-tert-butyl esterC13H25NO3[α]D25=-12.2 (c 1, CHCl3)Source of chirality: asymmetric dihydroxylationAbsolute configuration: (4S,5S)

(2S,3S)-Pent-1,2,3-triolC5H12O3[α]D25=-6.7 (c 1, CHCl3)Source of chirality: asymmetric dihydroxylationAbsolute configuration: (2S,3S)

(2S,3S)-1,3-O-Benzylidenepentane-1,2,3-triolC12H16O3[α]D25=-11.5 (c 0.48, CHCl3)Source of chirality: asymmetric dihydroxylationAbsolute configuration: (2S,3S)

(2R,3S)-2-Azido-1,3-O-benzylidenepentane-1,3-diolC12H15N3O2[α]D25=-8.8 (c 1, CHCl3)Source of chirality: asymmetric dihydroxylationAbsolute configuration: (2R,3S)

(2R,3S)-2-Azido-3-benzyloxypentan-1-olC12H17N3O2[α]D25=-12.2 (c 1, CHCl3)Source of chirality: asymmetric dihydroxylationAbsolute configuration: (2R,3S)

(5R,6S)-5-Azido-6-benzyloxyoct-3-ene-1-olC15H21N3O2[α]D25=-19.3 (c 0.52, CHCl3)Source of chirality: asymmetric dihydroxylationAbsolute configuration: (5R,6S)

1-Piperidin-2-yl-propan-1-olC8H17NO[α]D25=-8.9 (c 1.0, ethanol)Source of chirality: asymmetric dihydroxylationAbsolute configuration: (2S,3S)