Sodium acetate Rosenmund reduction

Successful Rosenmund reductions have been carried out in the presence of halogen acceptors, such as anhydrous sodium acetate 67, dimethylaniline 23), ethyidiisopropylamine (55), or 2,6-dimethylpyridine 10). 

Palladium catalysts are more often modified for special selectivities than platinum catalysts. Palladium prepared by reduction of palladium chloride with sodium borohydride Procedure 4, p. 205) is suitable for the reduction of unsaturated aldehydes to saturated aldehydes [i7]. Palladimn on barium sulfate deactivated with sulfur compounds, most frequently the so-called quinoline-5 obtained by boiling quinoline with sulfur [34], is suitable for the Rosenmund reduction [i5] (p. 144). Palladium on calcium carbonate deactivated by lead acetate Lindlar s catalyst) is used for partial hydrogenation of acetylenes to cw-alkenes [36] (p. 44). 

The reduction of acid chlorides may proceed at lower temperatures in the presence of a tertiary amine or sodium acetate. Peters and van Bekkum improved the method of Sakurai and Tanabe,260 using ethyldiisopropylamine, instead of A(7V-dimethylaniline, as a HC1 acceptor.261 Ethyldiisopropylamine had the advantage of forming an acetone soluble hydrochloride, and workup of the reaction mixture was easier when acetone was used as solvent. Reductions in the presence of these basic substances have been found to be especially effective when the acid chlorides are labile to decarbonylation. Examples of the use of base are shown in eqs. 13.139261 and 13.140.262 When the original procedure of the Rosenmund reduction was applied to 1 -/-bulylcyclohcxanc-carbonyl chloride, f-butylcyclohexanc was the sole product, compared to greater than 95% yield of the corresponding aldehyde in the presence of ethyldiisopropylamine or sodium acetate.261... 

Palladium-carbon sodium acetate Aldehydes from carboxylic acid chlorides Modified Rosenmund-Zetzscfae reduction... 

---