1: With Amberlite.(R). IRA-410 strongly basic ion exchange resin (OH form) in water T=0°C; 24 h; 2: With Amberlyst.(R). 15 strongly acidic ion exchange resin (H form) in dimethyl sulfoxide T=110°C; 5 h; Product distribution / selectivity;

tetrabutyl ammonium fluoride in tetrahydrofuran 2 h; Ambient temperature;

1: With Amberlite.(R). IRA-900 macroporous strongly basic ion exchange resin (OH form) in water T=-2°C; 2: With Amberlyst.(R). 15 strongly acidic ion exchange resin (H form) in dimethyl sulfoxide T=110°C; 5 h; Product distribution / selectivity;

1: With Amberlite.(R). IRA-402 strongly basic ion exchange resin (OH form) in water T=5°C; 12 h; 2: With Amberlyst.(R). 15 macroporous strongly acidic ion exchange resin (H form) in dimethyl sulfoxide T=110°C; 5 h; Product distribution / selectivity;

1: 89 percent / imidazole / dimethylformamide / 12 h / Ambient temperature 2: 1.) n-BuLi / 1.) hexane, THF, -40 deg C, 3 h, 2.) hexane, THF, rt, overnight 3: 83 percent / Bu4NF / tetrahydrofuran / Ambient temperature View Scheme

1: 1.) n-BuLi / 1.) hexane, THF, -40 deg C, 3 h, 2.) hexane, THF, rt, overnight 2: 83 percent / Bu4NF / tetrahydrofuran / Ambient temperature View Scheme

Yield given. Multistep reaction;