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Please login or sign up for a free trial to access the full content. Miscellaneous Reactions of Boron Alkanethiolates

DOI: 10.1055/sos-SD-139-00130

Witt, D.Science of Synthesis Knowledge Updates, (20113304.

An interesting example of the synthetic application of boron alkanethiolates has appeared in a study on the asymmetric reduction of alkyl aryl ketones.[‌102‌] (S)-N-Benzoylcysteine [(S)-2-benzamido-3-sulfanylpropanoic acid] is used to generate the chiral reducing reagent, which is believed to be a borohydride complex containing a B–S bond. Its application in the lithium borohydride reduction of ketones gives optically active alcohols 26 with enantiomeric excesses of up to 88% favoring the R configuration (Scheme 40).[‌102‌]

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Meeeeeeeeee 88

M8 ee (%) Meeee (%) Mee
Me 88 88 [‌888‌]
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Meeeeeeeeee 88

M8 M8 Meeee (%) Mee
(MM8)8Me Me 88 [‌888‌]
(MM8)8Me (MM8)8eMe 88 [‌888‌]
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(MM8)8Me eMe 88 [‌888‌]
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(M)-(+)-8-Meeeeeeeeeeeee (88, M8 = Me); Meeeeee Meeeeeeee:[‌888‌]

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Meeeeee-8-eee [88, M8 = (MM8)8Me; M8 = Me]; Meeeeee Meeeeeeee:[‌888‌]

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