1: With trimethylsilyl trifluoromethanesulfonate; N-ethyl-N,N-diisopropylamine in dichloromethane T=0 - 20°C; 2 h; Molecular sieve; 2: With Palau′chlor in dichloromethane T=20°C; 2 h; Molecular sieve; chemoselective reaction;

aluminium trichloride in 1,2-dichloro-ethane 2 h; Ambient temperature;