tri-tert-butyl phosphine; LiN(Cy)2; bis(dibenzylideneacetone)-palladium(0) in toluene T=20°C; 8 h;

2,3-dicyano-5,6-dichloro-p-benzoquinone in benzene 18 h; Heating;

sodium hydride in N,N-dimethyl-formamide T=20°C; Methylation; 10 h;

1: 1.) tris(dimethylamino)sulfonium difluorotrimethylsiliconate; 2.) 1 N HCl / 1.) pyridine, THF, -10 deg C to RT, 3.5 h; 2.) pyridine, THF, 5 min 2: 86 percent / DDQ / benzene / 18 h / Heating View Scheme

1: 1.) tris(dimethylamino)sulfonium difluorotrimethylsiliconate; 2.) 1 N HCl / 1.) pyridine, THF, -10 deg C to RT, 3.5 h; 2.) pyridine, THF, 5 min 2: 86 percent / DDQ / benzene / 18 h / Heating View Scheme