TY - JOUR
T1 - Enantiomeric purity of alkylmethylphenylsulfonium ions with chiral NMR shift reagents
T2 - Racemization by pyramidal inversion as observed by 1H NMR spectroscopy
AU - Green, Thomas K.
AU - Whetstine, Johnathan R.
AU - Son, Ea Ji Ru
PY - 1997/10
Y1 - 1997/10
N2 - Chiral tetrakis europate anions are used to spectroscopically resolve racemic mixtures of chiral alkylmethylphenylsulfonium ions using 1H NMR spectroscopy. The alkyl groups include ethyl, n-butyl, n-octyl and benzyl. The shift reagents include both Eu(tfc)3fod- and Eu(tfc)4-, where tfc is chiral (+)-3-(trifluoromethylhydroxymethylene)camphorate and fod is 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedione. Assignment of R and S configuration in the NMR spectrum of ethylmethylphenylsulfonium ion was made by synthesis of the R-enriched mixture of ethylmethyl-p-tolylsulfonium ion. Racemization of this mixture was observed by 1H NMR spectroscopy by heating to 60°C.
AB - Chiral tetrakis europate anions are used to spectroscopically resolve racemic mixtures of chiral alkylmethylphenylsulfonium ions using 1H NMR spectroscopy. The alkyl groups include ethyl, n-butyl, n-octyl and benzyl. The shift reagents include both Eu(tfc)3fod- and Eu(tfc)4-, where tfc is chiral (+)-3-(trifluoromethylhydroxymethylene)camphorate and fod is 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedione. Assignment of R and S configuration in the NMR spectrum of ethylmethylphenylsulfonium ion was made by synthesis of the R-enriched mixture of ethylmethyl-p-tolylsulfonium ion. Racemization of this mixture was observed by 1H NMR spectroscopy by heating to 60°C.
UR - http://www.scopus.com/inward/record.url?scp=0030882112&partnerID=8YFLogxK
U2 - 10.1016/S0957-4166(97)00383-2
DO - 10.1016/S0957-4166(97)00383-2
M3 - Article
AN - SCOPUS:0030882112
SN - 0957-4166
VL - 8
SP - 3175
EP - 3181
JO - Tetrahedron Asymmetry
JF - Tetrahedron Asymmetry
IS - 19
ER -