The direct asymmetric oxidation of 6,6'-bis(alkylsulfanyl)-2,2'-bipyridines 2a-e to non-racemic mono sulfoxides 3a-e and bis-sulfoxides 4a,c-e using either Davis oxaziridine or a modified Sharples reagent is reported. The use of isolated mono- and bis-sulfoxides as chiral auxiliaries was tested in either the asymmetric addition of the diethylzinc or allyl(trichloro)silane to benzaldehyde.
The first approach to optically active 2,2′-bipyridine alkyl sulfoxides
The synthesis of 6,6′-bis(alkylsulfanyl)-2,2′-bipyridines and their asymmetric oxidation to non-racemic 2,2′-bipyridine alkyl sulfoxides using either (+)-(8,8-dichlorocamphorylsulfonyl)oxaziridine or a modified Sharpless reagent is reported.