Comparative study of the N-isobutyl-(2E,6Z)-dodecadienamide chemical and electrochemical syntheses
作者:Agustín Palma、Jorge Cárdenas、Bernardo A. Frontana-Uribe
DOI:10.1039/b815745f
日期:——
In order to show the advantages and limitations of organic electrosynthesis in the total synthesis of a natural product, one of the promising green chemistry techniques in organic chemistry, the synthesis of N-isobutyl-(2E,6Z)-dodecadienamide (3) was undertaken. Chemical and electrochemical routes that use the same intermediates were used to carry out the syntheses. Four reactions were compared from a green chemistry point of view in the synthesis of 3: (a) alcohol to aldehyde oxidation, (b) the Horner–Emmons reaction, (c) carboxylic acid amidation with triphenylphosphonium ions and (d) the Wittig reaction. All the electrolyses were carried out in non-divided cells at a constant current. The electrochemical method in the oxidation reaction of alcohols and the carboxylic acid amidation gave better yields (95% and 67%, respectively) than the corresponding chemical reactions. The Horner–Emmons reaction gave the same yields in both techniques (80–85%); however, the electrochemical method was more environmentally friendly, due to the fact that the base used was electrogenerated, avoiding corrosive and sensitive base manipulation. Finally, the electrochemical Wittig reaction was unsuccessful in the different experimental conditions attempted, and only the chemical method produced the target product. This study demonstrated that organic electrochemistry can be a reliable method for the synthesis of important intermediates, but not all electrochemical reactions can compete with the already well-established methods of organic chemistry.
为了展示有机电合成在天然产物全合成中的优势和局限性,这是有机化学中有前景的绿色化学技术之一,我们进行了N-异丁基-(2E,6Z)-十二碳二烯酰胺(3)的合成。使用相同的中间体,通过化学和电化学途径进行了合成。从绿色化学的角度比较了3的合成中的四个反应:(a)醇到醛的氧化,(b)Horner-Emmons反应,(c)与三苯基膦离子进行的羧酸酰胺化,以及(d)Wittig反应。所有的电解都在恒定电流下在非隔膜电池中进行。在醇氧化反应和羧酸酰胺化中,电化学方法的产率(分别为95%和67%)高于相应的化学反应。Horner-Emmons反应在两种技术中的产率相同(80-85%);然而,由于所用的碱是通过电生成的,避免了腐蚀性和敏感的碱操作,电化学方法更为环境友好。最后,在尝试的不同实验条件下,电化学Wittig反应未获成功,只有化学方法产生了目标产物。这项研究表明,有机电化学可以是一种可靠的合成重要中间体的方法,但并非所有电化学反应都能与已建立的有机化学方法竞争。