Rosenmund还原

酰氯在 BaSO₄，喹啉-S或硫脲钝化的Pd催化剂的催化下氢化还原得到醛的反应。如果不进行钝化，生成的醛会继续还原成醇，因此可能的副产物有醇，酯和烷烃等。反应常用的溶剂有甲苯、二甲苯、THF等等，通常要求严格无水条件下进行，否则会有酸酐类副产物生成。硝基，卤素，酯基等基团在此反应条件下不会被还原。

反应机理

反应实例

【 Synthesis 1976, 767–768】

【 Helv. Chim. Acta 1990, 73, 405– 410】

【 Tetrahedron 2002, 58, 4851–4858】

【 Org. Process Res. Dev. 2012, 16, 1607-1617】

A pressure vessel is charged in order with 600 mL of dry toluene,25 g. (0.30 mole) of anhydrous sodium acetate,3 g. of dry, 10% palladium-on-carboncatalyst,23 g. (0.10 mole) of 3,4,5-trimethoxybenzoyl chloride, and 1 mL of Quinoline S. The pressure vessel is flushed with nitrogen, sealed, evacuated briefly, and pressured to 50 p.s.i. with hydrogen. The mixture is shaken with 50 p.s.i. of hydrogen for 1 hour at room temperature, then heated at 35–40° for 2 hours. Agitation is continued overnight while the reaction mixture cools to room temperature. The pressure on the vessel is released, the vessel is opened, and the mixture is filtered through10 gof Celite filter aid, and the insoluble material is washed with 25 mL of toluene. The combined filtrates are washed successively with 25 mL of 5% sodium carbonate solution and 25 mL of water. The toluene solution is dried over5 gof anhydrous sodium sulfateand filtered. The filtrate is concentrated by distillation at reduced pressure using a water aspirator. The residue is distilledthrough a 10-cm. Vigreux column with warm watercirculating through the condenser, to preventcrystallization of the distillate, yielding 12.5–16.2 g (64–83%) of 3,4,5-trimethoxybenzaldehyde, b.p. 158–161°C(7–8 mmHg.), m.p. 74–75°C.

【 Organic Syntheses, Coll. 1988，6，1007】