Reductive esterification of aromatic aldehydes using Zn/Ac2O/imidazole or Zn/Yb(OTf)3/(RCO)2O system
作者:Toshikazu Hirao、Sirida Santhitikul、Hiroki Takeuchi、Akiya Ogawa、Hidehiro Sakurai
DOI:10.1016/j.tet.2003.10.068
日期:2003.12
Benzaldehydes are reduced by metallic zinc in the presence of Ac2O and imidazole, giving the corresponding benzyl acetates in good yields. Reductive esterification of aromatic aldehydes is also carried out via gem-diacetoxy compounds. Carbonyl compounds are readily converted to the gem-diacyloxy compounds in excellent yields on treatment with 2 molar amounts of acid anhydride and 10 mol% of Yb(OTf)3
在Ac 2 O和咪唑的存在下,苯甲醛被金属锌还原,以高收率得到相应的乙酸苄酯。芳族醛的还原酯化也通过宝石-二乙酰氧基化合物进行。在室温下,在MeCN中用2摩尔量的酸酐和10 mol%的Yb(OTf)3处理后,羰基化合物很容易以优异的产率转化为宝石-二酰氧基化合物。由此形成的衍生自芳族醛的二酰氧基化合物被金属锌原位还原,得到相应的酯。