Camphor sulfonyl imine

Page and Bethell have also developed a catalytic process [122,123]. The most successful system is derived from camphor sulfonyl imine 62, giving enantiomer-ically enriched sulfides with ees of greater than 98% (Scheme 1.55) [123]. More recently, 3-substituted-l,2-benzisothiazole-l,1-dioxides have been employed [124, 125]. 

Davis et al. have extended this type of bis-metallation chemistry to a new method for synthesizing a-functionalized primary sulfonamides [5a].lV-Sulfonyl imines, such as 272, are readily prepared from camphor and the corresponding sulfonamide using TiCl4 as catalyst. These imines can be converted to the dianions 273 and monoalkylated to afford products 274 (Scheme 46). Hydrolysis of the alkylated imine affords a primary sulfonamide 275 in good overall yields. Unfor-... 

One can oxidize N-sulfonyl imines to the corresponding oxaziridines using oxidants such as a peracid or oxone [5 b, 93,94], Thus, Davis and coworkers have developed a biphasic procedure for converting imine 278 to frans-oxaziridine 279, in high yield [5b] [Eq. (65)]. Similarly, camphor-derived N-sulfonyl imines 277 and 268 can be oxidized to the endo oxaziridines 280 and 281, respectively [92,93] [Eq. (66), (67)]. Davis and others have now demonstrated the exceptional utility of oxaziridines as oxidants in organic synthesis and, in particular, the value of camphor-derived reagents, such as 280 and 281, in asymmetric synthesis [94,95],... 

Enantioselective fluorination. The N-fluoro sultams 1 and 2 are prepared from the imine available from ( + )-camphor-10-sulfonyl chloride. 

Preparation of the Auxiliary. A synthesis of the (1/ ) auxiliary has been reported starting from (-i-)-camphor (eq 1). Zinc reduction of the intermediate imine (2) followed by sulfonylation and ketone reduction with Ca(B 114)2 afforded the cis.endo product in 70-75% overall yield from camphorquinone (1). 

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