cesium fluoride in diethylene glycol dimethyl ether Ambient temperature;

1: 1.) triethylamine, 2.) conc. H2SO4 / 1.) DMF, from 10 to 20 deg C, 2.) ether, RT, overnight 2: 60 percent / CsF / bis-(2-methoxy-ethyl) ether / Ambient temperature View Scheme

1: dimethylformamide / 0.5 h / 0 °C 2: dimethylformamide View Scheme

in N,N-dimethyl-formamide Yield given;