trifluorormethanesulfonic acid; tetrabutylammomium bromide in dichloromethane T=25°C; 24 h; Yields of byproduct given;

1: methyl malonic acid diethylester With sodium hydride in tetrahydrofuran 0.5 h; 2: O-((E)-2-buten-1-yl)-N,N'-diisopropyl isourea With tris-(dibenzylideneacetone)dipalladium(0); triphenylphosphine in tetrahydrofuran T=20°C; Tsuji-Trost reaction; 24 h; Further stages.;

trifluorormethanesulfonic acid; tetrabutylammomium bromide in dichloromethane T=25°C; 24 h; Yields of byproduct given;