Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China.
Org Lett. 2009 Nov 19;11(22):5302-5. doi: 10.1021/ol902260a.
The key steps of cascade reactions employed in the syntheses of camptothecin-family alkaloids by Fortunak and Yao are intramolecular aza-Diels-Alder (IADA) reactions between in situ generated N-arylimidates and alkynes. The efficiencies of the IADA reactions are different but not well-understood. DFT calculations shown here provide insights into these two IADA reactions and well-rationalize why hexaphenyloxodiphosphonium triflate (Hendrickson reagent) as an amide-activating reagent is superior to trimethyloxonium fluoroborate.
福图纳克（Fortunak）和姚（Yao）在合成喜树碱族生物碱的级联反应中采用的关键步骤是原位生成的 N-芳基亚氨基甲酸酯和炔烃之间的分子内氮杂狄尔斯-阿尔德（IADA）反应。这些 IADA 反应的效率不同，但尚未得到很好的理解。这里的 DFT 计算提供了对这两个 IADA 反应的深入了解，并很好地解释了为什么六苯氧二磷三氟甲磺酸酯（亨德森试剂）作为酰胺活化试剂优于三甲基氧𬭩氟硼酸盐。
