in tetrahydrofuran 16 h; Inert atmosphereRefluxSchlenk technique;

1: With sodium t-butanolate; tris(dibenzylideneacetone)dipalladium(0) chloroform complex; 2-dicyclohexylphosphino-1,1'-biphenyl in toluene T=80°C; 16 h; 2: With Isolute HM-N in toluene T=20°C;