Oxindoles O-carbonylated

The absolute configuration of the rearranged products was again ascertained by determining the sign of optical rotation of one compound previously obtained by Fu [10]. Catalyst 6 was successfully tested in the rearrangement of O-carbonylated benzofuranones (Scheme 40.11) and of O-carbonylated oxindoles (Scheme 40.12), although for this last class of compounds the enantioselectivities were lower than those recorded by Hills and Fu [12]. 

Scheme 40.12 Enantioselective rearrangement of O-carbonylated oxindoles with catalyst (R)-6.

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