boron tribromide in hexane T=-10°C; 1 h; Yield given;

tetrabutyl ammonium fluoride in tetrahydrofuran T=50°C; 48 h;

1: 76 percent / NaH / 48 h / Heating 2: 90 percent Chromat. / 1 M LDA; HMPT / tetrahydrofuran / 1.) 40 min; 2.) 10 min; 3.) 30 min; 4.) 4 h to RT 3: 1 M BBr3 / hexane / 1 h / -10 °C View Scheme

sodium ethanolate