A new
CuI/1,10-phen-catalyzed reaction for the synthesis of 3-ylideneoxindoles
from readily available isatins and ethyl isocyanoacetate, in which
ethyl isocyanoacetate acts as a latent two-carbon donor like the Wittig
reagent, is reported. A tandem procedure including 1,3-dipolar cycloaddition/inverse
1,3-dipolar ring opening/olefination allows the preparation of 3-ylideneoxindoles
with broad functional group tolerance