1: lithium tert-butylate / methanol / 0.5 h / 8 - 22 °C 2: lithium tert-butylate / N,N-dimethyl-formamide; tetrahydrofuran / 44 h / 20 °C / |Cooling with ice 3: N-methyl-acetamide; N-bromosuccinmide / chloroform / 18 h / 30 °C / |Reflux View Scheme

1: lithium tert-butylate / N,N-dimethyl-formamide; methanol; tetrahydrofuran / 21 h / 5 - 24 °C 2: N-methyl-acetamide; N-bromosuccinmide / chloroform / 18 h / 30 °C / |Reflux View Scheme