dimethylsulfide borane complex in tetrahydrofuran T=60°C; Reduction; 6 h;

in tetrahydrofuran (N2); soln. cooled in an ice-bath; BH3*Me2S gradually added; mixt. heated, 60°C, 6 h; concd. to dryness; residue mixed with aq.HCl; mixt. refluxed, 2 h; neutralised (Na2CO3); extd. (diethyl ether); org. soln. dried over MgSO4; evapd. to dryness;

1: triethylamine / 14 h / 20 °C 2: 71.6 percent / BH3*Me2S / tetrahydrofuran / 6 h / 60 °C View Scheme