pyrrolidine acetic acid in benzene T=20°C; Knoevenagel condensation; 24 h;

toluene-4-sulfonic acid in dichloromethane T=0°C; 0.166667 h;

potassium hydroxide; potassium hexacyanoferrate(III)

hydrogenchloride 1.) ether, THF;

1: 92 percent / 1) piperidinium acetate; 2) aq. 10 percent citric acid / acetonitrile / 1 h 2: 84 percent / aq. KOH, aq. K3<Fe(CN)6> View Scheme

in toluene 8.5 h; Heating; Yield given. Yields of byproduct given;

in toluene 8.5 h; Heating; Yield given;

1: 5-isobutylidene-2,2-dimethyl-[1,3]dioxan-4-one; (trifluoromethyl)-trimethylsilane With sodium acetate in N,N-dimethyl-formamide T=50°C; 2 h; Inert atmosphere; 2: With hydrogenchloride in water; N,N-dimethyl-formamide T=120°C; 1 h; Inert atmosphere; 3: benzyl bromide With potassium carbonate in N,N-dimethyl-formamide T=20°C; 2 h; Inert atmosphere;