1: 70 percent / sodium dichromate, H2SO4(conc.) / H2O / Ambient temperature 2: 62 percent / BNAH / hexamethylphosphoric acid triamide / 48 h / Ambient temperature; Irradiation View Scheme

sodium dichromate; sulfuric acid in water Ambient temperature;

With  triethylamine; triphenylphosphine in  tetrachloromethane 2 h;  Heating;