1: 91 percent / BF3*Et2O / CH2Cl2 / -78 °C 2: Hg(ClO4)2*3H2O, 6N HCl / H2O / 25 °C 3: 81 percent / 1.) MsCl, Et3N, DMAP; 2.) DBU / CH2Cl2 / 0 °C 4: 78 percent / CF3COOH, / H2O / 50 °C View Scheme

silver trifluoroacetate; (2Z,6E)-3-lt;lt;(tert-butyl)dimethylsiloxygt;methylgt;-7-methyl-9-(2',6',6'-trimethylcyclohex-1'-enyl)nona-2,6-dien-1-ol in dichloromethane