iodine; lithium diisopropyl amide in tetrahydrofuran; hexane T=-75°C;

1: 86 percent / KF / tetrahydrothiophene 1,1-dioxide / 20 h / 180 °C 2: 73 percent / lithium diisopropylamide; iodine / tetrahydrofuran; hexane / -75 °C View Scheme

2,2,6,6-tetramethylpiperidinyl-lithium; water in tetrahydrofuran; methanol T=-100 - -75°C;