Novel deacylation of α-bromo-β-diketones using silica sulfuric acid (SSA) has been developed. Deacylation of 3-bromopentane-2,4-diones and 2-bromobutane-1,3-diones were carried out in the presence of SSA in dichloroethane under mild conditions to obtain the corresponding α-bromo ketones in good to excellent yields. SSA also promoted the Friedel–Crafts type alkylation of benzene with 3-(sec-alkyl)-2,4-pentanediones to give the corresponding triarylmethanes in high yields in benzene.
利用
二氧化硅硫酸(S
SA)开发出了α-
溴-
β-二酮的新型脱乙酰化方法。在 S
SA 存在下,在温和条件下,在
二氯乙烷中对
3-溴戊烷-2,4-二酮和
2-溴丁烷-1,3-二酮进行了脱乙酰化反应,得到了相应的α-
溴酮,收率从良好到极佳。S
SA 还能促进苯与 3-(仲烷基)-
2,4-戊二酮的 Friedel-Crafts 型烷基化反应,从而在苯中高产率地得到相应的三芳基
甲烷。