4-methyl-morpholine; silver trifluoroacetate in tetrahydrofuran; water T=0 - 20°C; Wolff rearrangement; 8 h;

1.1: Et3N; i-BuOCOCl / tetrahydrofuran / 0.25 h / -25 °C 1.2: 50 percent / tetrahydrofuran; diethyl ether / 0 - 20 °C 2.1: 71 percent / CF3COOAg; NMM / tetrahydrofuran; H2O / 8 h / 0 - 20 °C View Scheme