131. Asymmetric Induction at C(β) and C(α) of N-Enoylsultams by Organomagnesium 1,4-Addition/Enolate Trapping
     Oppolzer, W.; Poli, G.; Kingma, A. J.; Starkemann, C.; Bernardinelli, G.
     Helv. Chim. Acta 1987, 70, 2201-2214

The 1,4-addition of alkylmagnesium chlorides to conjugated N-enoylsultams and subsequent ‘enolate trapping’ with aq. NH₄Cl or MeI/hexamethylphosphoric triamide generated centers of asymmetry at C(β) and/or at C(α) with good to excellent π-face defferentiation as demonstrated by the conversions 1→2, 1→4, and 8→9. This holds also for the regioselective 1,4-addition of EtMgC1 to a dienoylsultam (1516). Reactive conformations 1^≠, 8^≠, 13, and 14 are postulated in agreement with X-ray evidence which also served for the structure determination of the product 9j.

DOI : 10.1002/hlca.19870700825 

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