619326-29-3Relevant articles and documents
Structure and Absolute Stereochemistry of Thioacetal Sulphoxides Obtained by Fungal Metabolism of 2 Alkyl-1,3-Dithianes
Auret, Barbara J.,Boyd, Derek R.,Cassidy, E. Sally,Hamilton, Robert,Turley, Fiona,Drake, Alex F.
, p. 1547 - 1552 (1985)
Monosulphoxide metabolites of 2-methyl-, 2-t-butyl-, 2,2-dimethyl-, and 2-methyl-2-t-butyl-1,3-dithiane have been isolated after addition of the thioacetals to growing cultures of the fungi Aspergillus foetidus, Mortierella isabellina and a Helminthosporium species.The optical yields of the chiral monosulphoxide metabolites (0-72percent) were determined by n.m.r. analysis in (-)-phenyl- or 1-(+)-9-anthryl-2,2,2-trifluoroethanol-CDCl3 solvent mixtures.The signs of Cotton effects obtained from c.d. spectra have been used to assign the absolute stereochemistry of the chiral thioacetal sulphoxides.Optically pure samples 2,2-dimethyl-1,3-dithiane 1-oxide, cis-2-methyl-1,3-dithiane 1-oxide, and trans-2-methyl-1,3-dithiane 1-oxide, have been obtained by a chemical resolution method which provides confirmation of optical yields and absolute stereochemistry.The fungal metabolism results indicate that the mono-oxygenase enzymes can stereodifferentiate between prochiral (diastereotopic) Ione pairs on a sulphur atom and also between prochiral (enantiotopic) thioalkyl substituents on a carbon atom during the formation of monosulphoxides.
Chemistry of oxaziridines. 17. N-(phenylsulfonyl)(3,3-dichlorocamphoryl)oxaziridine: A highly efficient reagent for the asymmetric oxidation of sulfides to sulfoxides
Davis, Franklin A.,Thimma Reddy,Han, Wei,Carroll, Patrick J.
, p. 1428 - 1437 (2007/10/02)
The synthesis, structure, and enantioselective oxidations of a new chiral N-sulfonyloxaziridine 12c [3,3-dichloro-1,7,7-trimethyl-2'-(phenylsulfonyl)spiro[bicyclo[2.2.1]heptane-2, 3'-oxaziridine]] are reported. This oxidant, which exhibits remarkably high and predictable ee's for the enantioselective oxidation of prochiral sulfides to sulfoxides, is prepared in three steps from (+)- or (-)-camphor in 50% overall yield. Steric effects are primarily responsible for the molecular recognition and are predictable using a simple active-site model where the nonbonded interactions between the RL and RS groups of the sulfide (RL-S-RS) and the active-site surface are minimized in a planar transition-state structure. The fact that alkyl aryl sulfides give high ee's in nonpolar solvents suggests that there is also a stereoelectronic component to the molecular recognition. High ee's (>90%) are anticipated for those sulfides where the difference in size of the groups directly bonded to the sulfur atom is large, i.e., aryl, tert-butyl vs CH2R (R = H, alkyl, benzyl, etc). The X-ray structure and studies with the dihydro, difluoro, and dibromo oxaziridines 12a, 12b, and 12d reveal that the exceptional enantioselectivities displayed by 12c are a consequence of a molecular cleft or groove, defined by the oxaziridine chlorine atoms and phenylsulfonyl group, on the active-site surface.
