Dess-Martin periodane in dichloromethane; acetonitrile T=25°C; 1 h;

4-methylmorpholine N-oxide in dichloromethane T=20°C; Cycloaddition; Khand cycloaddition;

1: ethynylmethyl carbinol With dicobalt octacarbonyl in dichloromethane T=25°C; 5 h; 2: benzoic acid vinyl ester With 4-methylmorpholine N-oxide in dichloromethane T=25°C; Khand cyclization; 16.5 h;

pyridinium p-toluenesulfonate in methanol 1 h; Heating;

triethylamine in methanol T=37°C; 24 h;