tetrabutyl ammonium fluoride in ethylenediamine; N,N-dimethyl-formamide T=45°C; 48 h; Yield given. Yields of byproduct given. Title compound not separated from byproducts;

tert.-butyl lithium in hexane a) -78 deg C, 1h b) 0 deg, 2h c) room temperature, 18h;

1: 85 percent / NaH / dimethylformamide / 1. 0 deg C 2. room temperature, 1h 2: 75 percent / t-BuLi / hexane / a) -78 deg C, 1h b) 0 deg, 2h c) room temperature, 18h View Scheme