10,2-Camphorsultam derivative preparation

For the preparation of chiral nonracemic dipeptide isosteres, Otaka and Fujii also reported the use of camphorsultam derivative 49, which was prepared in optically pure form through the Reformatsky reaction of BrCF2C02Et with a chiral imine (see Scheme 10.15) [25]. 

In addition to the synthesis of enantiomerically pure (camphorylsulfonyl)oxaziridine7 and its derivatives,8 the (camphorsulfonyl)imine has been used in the preparation of (-)-2,10-camphorsultam (Oppolzers auxiliary),6-9 (+)-(3-oxocamphorysulfonyl)oxaziridine10 and the N-fluoro-2,10-camphorsultam, an enantioselective fluorinating reagent.11... 

A method of preparing either cis- or trans-aziridine carboxylates (39) from A-diphenylphosphinylimines (37) and the chiral enolate (36) derived from A-bromo-acetyl 25-2,10-camphorsultam (35) has been reported.54 When the arylimine is substituted in the ortho -position, the product is either a mixture of cis- and trans-aziridine or only the trans-isomer. When the ortho-substituent is H or NO2, only a cz s-aziridine is obtained. The suggested mechanism is partially shown in Scheme 18. Both steric and inductive effects of the ortho- substituent affect the stereochemistry of the addition complex (38) and the stereochemistry of the final aziridine. 

Preparation of Derivatives. IV-EnoyP and IV-acyl sultam derivatives are readily prepared using either Sodium Hydride-acid chloride or Triethylamine-add chloride single-step protocols. Various alternative derivatization procedures that work for the 10,2-camphorsultam auxiliary would also be expected to be effective. 

N-Arylated 1,3-propanesultams 236 (R =Ar, R = H) are efficiently prepared from a Pd-catalyzed cross-coupling reaction with different aryl bromides in the presence of Xantphos <2004TL3305>. N-Fluorinated (-l-)-camphorsultams 237 (X = H, Cl, OMe R = F) have been prepared the corresponding imine 16 and difluoro derivative 238 were formed as by-products. The use of 237 is reported in Section 4.05.12.1 <1998JOC9604>. The syntheses of Ar-(l-alkynyl)-Oppolzer s sultams are reported in Section 4.05.6.3.4. Many examples of acylated Oppolzer s sultams are reported in Section 4.05.12.1. 

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