New homogeneously and heterogeneously [Pd/Cu]-catalysed C3-alkenylation of free NH-indoles

A new palladium/copper catalytic procedure for the C-3-alkenylation of free NH-indoles is reported. Using homogeneous or heterogeneous hetero-bimetallic [Pd/Cu] -catalysts under mild reaction conditions (10 mol% Pd-catalyst and 10 mol% Cu-catalyst, 70 degrees C, air), substituted indoles are fully (58-82% isolated yields) and selectively (75-100% selectivity) converted to the expected 2-substituted-3-vinyl indoles. (C) 2007 Elsevier B.V. All rights reserved.