A practical procedure for the removal of the phenylethanol moiety from phenylglycinol-derived lactams

Chiral non-racemic bicyclic lactams derived from phenylglycinol have been appointed as key building blocks for the preparation of enantiopure nitrogen compounds. The removal of the chiral inductor leading to substituted piperidones by using air or oxygen in basic media is presented.

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(6S)-1-[(1R)-2-Hydroxy-1-phenylethyl]-6-[1-(methoxymethyl)indol-3-yl]piperidin-2-oneC23H26N2O3[α]D22=+25.5 (c 2.56, CHCl3)Source of chirality: (R)-phenylglycinolAbsolute configuration: (6S)

(3R,6R)-6-Allyl-3-ethyl-1-[(1S)-2-hydroxy-1-phenylethyl]piperidin-2-oneC18H25NO2[α]D22=-63.1 (c 1.25, CHCl3).Source of chirality: (S)-phenylglycinolAbsolute configuration: (3R,6R)

3,3-Diallyl-1-[(1S)-2-hydroxy-1-phenylethyl]piperidin-2-oneC19H25NO2[α]D22=+1.4 (c 1.0, MeOH)Source of chirality: (S)-phenylglycinolAbsolute configuration: (1S)

(6S)-[1-(Methoxymethyl)indol-3-yl]piperidin-2-oneC15H18N2O2[α]D22=-55.5 (c 0.6, MeOH)Source of chirality: (R)-phenylglycinolAbsolute configuration: (6S)

(5S,6S)-6-Allyl-5-ethylpiperidin-2-oneC10H17NO[α]D22=-23.7 (c 2.0, CHCl3)Source of chirality: (S)-phenylglycinolAbsolute configuration: (3S,6S)

(3R,6R)-6-Allyl-3-ethylpiperidin-2-oneC10H17NO[α]D22=+20.1 (c 0.63, MeOH)Source of chirality: (S)-phenylglycinolAbsolute configuration: (3R,6R)

(3S,6R)-6-Allyl-3-ethylpiperidin-2-oneC10H17NO[α]D22=-5.4 (c 0.7, MeOH)Source of chirality: (S)-phenylglycinolAbsolute configuration: (3S,6R)