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A chiral synthesis of (2 S , 3 S )‐phenylalanine‐3‐ 2 H via boronic esters
Author(s) -
Matteson Donald S.,
Beedle Ellen C.,
Christenson Erik,
Dewey Michael A.,
Peterson Mark L.
Publication year - 1988
Publication title -
journal of labelled compounds and radiopharmaceuticals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 47
eISSN - 1099-1344
pISSN - 0362-4803
DOI - 10.1002/jlcr.2580250613
Subject(s) - chemistry , sodium azide , diastereomer , lithium (medication) , enantiomer , sodium chlorite , phenylalanine , azide , reagent , medicinal chemistry , enantiomeric excess , alcohol , sodium , stereochemistry , organic chemistry , catalysis , enantioselective synthesis , amino acid , medicine , chlorine dioxide , endocrinology , biochemistry
Reduction of (s)‐pinanediol ( S )[(phenyl) (chloro)‐methyl]boronate (1) with lithium triethylborodeuteride yielded ( s )‐pinanediol ( R )‐[(phenyl)methyl]boronate‐α‐ 2 H (2). The chiral purity of 2 was measured via peroxidic oxidation to ( S )‐benzyl alcohol‐α‐ 2 H (3), which was analyzed with an NMR chiral shift reagent. (Dichloro‐methyl)lithium converted 2 to ( s )‐pinanediol (1 S ,2 S )‐1‐chloro‐2‐phenylethylboronate‐2‐ 2 H (4), which with sodium azide yielded ( s )‐pinanediol (1 R ,2 S )‐1‐azido‐2‐phenylethylboronate‐2‐ 2 H (5). (Dichloromethyl) lithium with 5 yielded ( s )‐pinanediol (1 S , 2 S ,3 S )‐1‐chloro‐2‐azido‐3‐phenylpropylboronate‐3‐ 2 H (6), which was oxidized by sodium chlorite to (2 S ,3 S )‐2‐azido‐3‐phenylacetic acid‐3‐ 2 H (7). Hydrogenation of 7 yielded (2 S ,3 S )‐phenylalanine‐3‐ 2 H (8) in high diastereomeric and enantiomeric purity.