1: in N,N-dimethyl acetamide T=60°C; 2: With hydrogenchloride in methanol; N,N-dimethyl acetamide; water 2 h; Heating / reflux; Product distribution / selectivity;

trifluoroacetic acid in dichloromethane T=20°C; 2 h; Product distribution / selectivity;

iron; acetic acid in ethyl acetate T=65°C; 2 h; Product distribution / selectivity;

1: trichlorophosphate / N,N-dimethyl-formamide / 4 h / 110 °C 2: sodium t-butanolate / 9,9-dimethyl-4,5-bis(diphenyl-phosphino)xanthene; tris-(dibenzylideneacetone)dipalladium(0) / toluene / 2 h / Inert atmosphere; Reflux 3: 1,1'-bis-(diphenylphosphino)ferrocene; tris-(dibenzylideneacetone)dipalladium(0) / N,N-dimethyl-formamide / 0.5 h / 170 °C / Reflux; Inert atmosphere 4: trifluoroacetic acid / dichloromethane / 3 h / 20 °C View Scheme

1: sodium t-butanolate / 9,9-dimethyl-4,5-bis(diphenyl-phosphino)xanthene; tris-(dibenzylideneacetone)dipalladium(0) / toluene / 2 h / Inert atmosphere; Reflux 2: 1,1'-bis-(diphenylphosphino)ferrocene; tris-(dibenzylideneacetone)dipalladium(0) / N,N-dimethyl-formamide / 0.5 h / 170 °C / Reflux; Inert atmosphere 3: trifluoroacetic acid / dichloromethane / 3 h / 20 °C View Scheme

1: 1,1'-bis-(diphenylphosphino)ferrocene; tris-(dibenzylideneacetone)dipalladium(0) / N,N-dimethyl-formamide / 0.5 h / 170 °C / Reflux; Inert atmosphere 2: trifluoroacetic acid / dichloromethane / 3 h / 20 °C View Scheme