Oppolzer s camphorsultam

Asymmetric radical reactions. Curran et al,3 report several asymmetric reactions of radicals derived from Oppolzer s camphorsultam. Thus the reaction of the iodosultam 1 with allyltributyltin initiated by triethylborane provides an epimeric... 

Highly diastereoselective alkyl radical addition to Oppolzer s camphorsultam derivative (33) of oxime provides enantiomerically pure a-alkyl-a-amino acid derivative (34) at — 78 °C by the same method as shown in eq. 10.16. Moreover, enantioselective tandem radical 1,2-difunctionalization of cinnamamide (35) can be carried out with high stereoselectivity, using the chelation manner of the cinnamamide and a chiral bisoxazoline ligand on Mgl2, as shown in eq. 10.17. 

The chiral auxiliary approach. Poncas group has worked with chiral sulfur moieties like 10-methylthioisoborneol, Oppolzer s camphorsultam or chiral oxazolidinones which gave excellent results in stereo control and yields [95-100]. Recently they have reported that chiral alkynylthiols like 46 exhibit excellent diastereoselectivities in both inter- and intramolecular PKR, and have used this approach for the synthesis of 47, an intermediate in the synthesis of (+)-15-nor-pentelenene (48) (Scheme 15) [101,102]. 

Chiral auxiliary approaches have been examined for the production of enantioenriched products through [2,31-rearrangements. For example, Sweeney and coworkers treated N,N-dimethylammonium salts 186 with sodium hydride to generate ammonium ylides bearing Oppolzer s camphorsultam, which underwent diastereoselective [2,31-Stevens rearrangements to enantioenriched products 187 [Scheme 1S.44. Eq. Oppolzer s camphorsultam was also compatible with our group s palladium-catalyzed tandem allylic amination/[2,31-Stevens rearrangement of tertiary amines [Scheme 1S.44. Eq. 2) ... 

The related phthallmldyl dlazoacetate (25) has yielded series of dlazoacetamldes bearing Oppolzer s camphorsultam chiral auxiliary (eq 17). ... 

Of great interest is the use of Oppolzer s camphorsultam as chiral auxiliary in a zinc-mediated allylation of oximes in the Luche conditions ... 

Ring-opening of methylenecyclopropanes in the presence of Pcl(O) or Ni(0) catalysts has served as an alternative pathway to gain access to reactive tri-methylenemethanes for [2-i-3]-cycloaddition reactions [40]. Binger obtained excellent asymmetric induction with chiral acrylamide 81 derived from Oppolzer s camphorsultam (Equation 9) [111]. Ni-catalyzed opening of cyclopropane 150 and cycloaddition afforded the desired adduct 151 in 99 1 dr. 

Indium-mediated allylation reactions of a-keto imides derived from Oppolzer s sultam proceeded in aqueous THF in good yields and excellent diastereoselectivity (Eq. 11.43).74 The indium-mediated allylation of the Oppolzer camphorsultam derivatives of glyoxylic oxime ether... 

Oppolzer s chiral auxiliary,6 (-)-2,10-camphorsultam, is useful in the asymmetric Diels-Aider reaction,3.4 and for the preparation of enantiomerically pure p-substituted carboxylic acids7 and diols,8 in the stereoselective synthesis of A2-isoxazolines,9 and in the preparation of N-fluoro (-)-2,10-camphorsultam, an enantioselective fluorinating reagent.10... 

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. 

Oppolzer s acylated camphorsultams (147, Equation 12) remain a classic among chiral auxiliaries for asymmetric synthesis and have been successfully applied in a variety of mechanistically distinct chemical transformations [88, 91]. The corresponding enolates can readily be prepared with a variety of strong bases and have been shown to undergo diastereoselective alkylation with a range of activated and non-activated electrophilic reagents. An illustrative example is the formation of 149 in dr >99 1 [91]. The sense... 

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