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Generation of Stereocenters Around a C 3 ‐Symmetric Cyclotriveratrylene Crown
Author(s) -
Sansévérino Julien,
Aubert Emmanuel,
Espinosa Enrique,
Chambron JeanClaude
Publication year - 2012
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201101780
Subject(s) - chemistry , diastereomer , stereocenter , oxaziridine , chirality (physics) , enantiomer , stereochemistry , reagent , dichloromethane , enantioselective synthesis , organic chemistry , catalysis , nambu–jona lasinio model , chiral symmetry breaking , physics , quantum mechanics , quark , solvent
The oxidation of racemic methylthio‐substituted C 3 ‐symmetric cyclotriveratrylene (CTV) 2 produces the corresponding trisulfoxides 3 as follows. Oxidation with m ‐chloroperoxybenzoic acid ( m ‐CPBA) in dichloromethane leads to the formation of a distribution of the four possible diastereomers that is relatively close to the statistical outcome, in which the C 3 ‐symmetric stereoisomers are the minor species. In contrast, the optically active Davis reagent [oxaziridine (+)‐ 4 ] in carbon tetrachloride at room temperature leads to a biased (73 %) distribution in favor of the C 3 ‐symmetric MRRR / PSSS diastereomer of 3 with 56 % ee ( PSSS enantiomer according to the model of Davis). Interestingly, when the oxidation is carried out in toluene at reflux, the distribution is switched to approximately equal amounts of the C 3 ‐symmetric MSSS / PRRR and asymmetric MRSS / PSRR diastereomers of 3 . Overall, however, these results point to the negligible role played by the chirality of the CTV platform on the induction of chirality at the sulfur prochiral centers.