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Synthesis of Chiral 2,5‐Bis(oxazolinyl)thiophenes and Their Application as Chiral Shift Reagents for 1,1′‐Bi‐2‐naphthol
Author(s) -
Gao MingZhang,
Wang Bo,
Liu HanBiao,
Xu ZunLe
Publication year - 2002
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.20020200117
Subject(s) - chemistry , oxazoline , thiophene , chirality (physics) , reagent , ring (chemistry) , stereochemistry , ethanolamine , medicinal chemistry , organic chemistry , catalysis , chiral symmetry breaking , symmetry breaking , physics , quantum mechanics , nambu–jona lasinio model
A series of C 2 ‐symmetrical chiral 2,5‐bis(4′‐alkyloxazolin‐2‐yl) thiophenes (thiobox) have been synthesized from thiophene‐2, 5‐dicarboxylic acid by sequential amidation with a chiral ethanolamine, conversion of hydroxyl to chloro group, and base‐promoted oxazoline ring formation. As demonstrated by ( ‐ )‐2, 5‐Ws[4′‐( S)‐isopropyloxazolin‐2′‐yl] thiophene, these thiobox systems exhibited remarkable chirality recognition of 1, 1′‐bi‐2‐naphthol giving rise to pronounced shifts in the l H NMR signals of the latter axial chiral compound at the positions of C‐3, C‐4, C‐5, and C‐8.