1: 26 percent / CuI, (CH3)2S / tetrahydrofuran / a) -20 deg C, 10 min, b) RT, 1 h 2: 1-benzyl-3-carbamoylpyridinium hexafluorophosphate / acetonitrile / 16 h / Ambient temperature View Scheme

sodium dithionite in water; toluene T=100°C; 0.25 h;

in acetonitrile T=20°C; Rate constantEquilibrium constant;