[Ru(CO)2(4,5-bis(diphenylphosphino)-9,9-dimethyl-9H-xanthene)]2; [Ru(CO)2(4,5-bis(diphenylphosphino)-9,9-dimethyl-9H-xanthene)]2; toluene-4-sulfonic acid in 1,1-dimethylpropan-1-ol T=120°C; regioselective reaction;

toluene-4-sulfonic acid in ethanol Fischer cyclization; 1 h; Heating;

in 2-methoxy-ethanol T=80 - 130°C; 1.5 h;

hydrogenchloride; water; acetic acid