n-butyllithium in tetrahydrofuran; hexane BuLi in hexane is added to a soln. of ether-compd. in THF at -78°C, the mixt. is stirred for 1 h under N2, triisopropyl borate is added and the mixt. is stirred for 1,5 h, then warmed to room temp, HCl and Et2O is added; the organic layer is separated and washed with HCl and water, the solvent is evaporated, the residue is stirred with light petroleum at 0°C, the ppt. is washed with ice cold light petroleum, crystn. from CHCl3-light petroleum, elem. anal.;

1: 87 percent / NaBF4 / CH2Cl2 / 1.5 h / 0 °C 2: 9 percent / CrCl2 / dimethylformamide / 12 h / 25 °C View Scheme

chromium dichloride; silver(l) oxide in tetrahydrofuran T=65°C;

palladium diacetate; triphenylphosphine; p-benozquinone T=20°C; P=760.051 Torr; 2 h;

oxygen; Mn(OAc)3•2H2O in 1,2-dichloro-ethane T=80°C; 4 h;

palladium diacetate; triphenylphosphine; p-benozquinone T=20°C; P=760.051 Torr; 0.5 h;

palladium diacetate; triphenylphosphine; p-benozquinone T=20°C; P=760.051 Torr; 2 h;