SYNTHESIS, CONFIGURATION, AND OPTICAL PURITY OF ASYMMETRIC PRIMARY ALCOHOLS

Samples of optically active and racemic isobutyl-1-di alcohols required for the determination of the stereochemistry of the biosynthesis of the cholesterol side chain were prepared. Asymmetric reduction of isobutyral-dehyde with (-)- and (+)-diisopinocampheyldeuterioboranes gave (-)-(1R)-isobutyl-1-d1 alcohol (optical purity 27.1%) and (+)-(1S)-isobutyl-1-d1 alcohol (optical purit27.6%), respectively. Two specimens of optically pure (1S)-isobutyl-1-d1 alcohol containing 80.5 and 70.2% deuterium were obtained by yeast reduction of samples of isobutyraldehyde-1-d containing 100 and 98.4% deuterium. The (+)-(3R)- and (-)-(3S)- isocaproic-3-d1 acids, previously described by us, were shown to be 34.0 and 32.6% optically pure, respectively. The (+)-(1S)- and the (-)-(1R)-isobutyl-1-d1 alcohol were related to (R)- and (S)-glyceraldehyde, respectively. The method of Horeau, studies utilizing the specificity of NAD+ and yeast alcohol dehydrogenase (YADH), and a modified interpretation of the mode of reduction of ketones and aldehydes with (+)- and (-)-diisopinocampheylboranes led to identical configurational conclusions. © 1969, American Chemical Society. All rights reserved.