179. C. Fruit, P. Müller,
     “Intramolecular Asymmetric Amidations of Sulfonamides and Sulfamates Catalyzed by Chiral Dirhodium(II) Complexes”
     Helv. Chim. Acta 2004, 87, 1607-1615.

Enantioselective intramolecular amidation of aliphatic sulfonamides was achieved for the first time by means of chiral carboxylatodirhodium(II) catalysts in conjunction with PhI(OAc)₂ and MgO in high yields and with enantioselectivities of up to 66% (Scheme?3, Table?1). The best results were obtained with [Rh₂{(S)-nttl)₄] and [Rh₂{(R)-ntv)₄] as catalysts ((S)-nttl=(αS)-α-(tert-butyl)-1,3-dioxo-2H-benz[de]isoquinoline-2-acetato, (R)-nto=(αR)-α-isopropyl-1,3-dioxo-2H-benz[de] isoquinoline-2-acetato). In addition, these carboxylatodirhodium(II) catalysts were also efficient in intramolecular amidations of aliphatic sulfamates esters, although the enantioselectivity of these latter reactions was significantly lower (Scheme?4, Table?3).

DOI : 10.1002/hlca.200490148 

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