Alonso Diego A, Nájera Carmen, Pacheco M Carmen
Departamento de Química Orgánica and Instituto de Síntesis Orgánica, Facultad de Ciencias, Universidad de Alicante, Apartado 99, E-03080 Alicante, Spain.
J Org Chem. 2004 Mar 5;69(5):1615-9. doi: 10.1021/jo035761+.
Phosphane-free oxime-derived palladacycle 2 is an efficient precatalyst for the copper-free acylation of terminal alkynes with different carboxylic acid chlorides in toluene in the presence of 3 equiv of TEA as base, giving the corresponding ynones in good yields. The coupling reaction can normally be performed under air or under inert atmosphere when very low catalyst loadings (10(-3) mol % Pd) (turnover numbers (TONs) up to 23,000, turnover frequencies (TOFs) up to 958 h(-1)) or sensitive carboxylic acid chlorides are used. In addition, Pd(OAc)(2) has been shown as an efficient catalyst for the ligandless process, although usually working under higher loading conditions. This new protocol allows one to perform the synthesis of ynones at 110 degrees C, at room temperature, or under microwave irradiation conditions.
不含膦的肟衍生钯环配合物2是一种高效的预催化剂，在3当量三乙胺作为碱的存在下，可使末端炔烃与不同的酰氯在甲苯中进行无铜酰化反应，以良好的产率得到相应的炔酮。当使用非常低的催化剂负载量（10⁻³ mol% Pd）（转换数（TONs）高达23,000，转换频率（TOFs）高达958 h⁻¹）或敏感的酰氯时，偶联反应通常可在空气或惰性气氛下进行。此外，醋酸钯（Pd(OAc)₂）已被证明是无配体反应过程中的一种高效催化剂，尽管通常在较高负载条件下工作。这种新方法允许在110℃、室温或微波辐射条件下进行炔酮的合成。
