A Synthetic Model for the [4+2] Cycloaddition in the Biosynthesis of the Brevianamides, Paraherquamides, and Related Compounds
作者:Juan F. Sanz-Cervera、Robert M. Williams、J. Alberto Marco、José Marı&#x;a López-Sánchez、Florenci González、Marı&#x;a Eugenia Martı&#x;nez、Félix Sancenón
DOI:10.1016/s0040-4020(00)00573-1
日期:2000.8
The reactivity of model systems for the proposed [4+2] cycloaddition in the biosynthesis of the brevianamides, paraherquamides, and marcfortines is explored. The model for the intermolecular reaction reveals that the cycloaddition takes place under mild conditions only if activated, very reactive dienophiles are used. When relatively unreactive dienophiles such as cyclopentene and cyclohexene are used
探索了模型系统的反应性,用于拟南芥中的[4 + 2]环加成反应在短毛酰胺,副硬脂酰胺和水飞蓟宾的生物合成中。分子间反应的模型表明,只有在使用活化的,反应性很强的亲二烯体的情况下,环加成反应才会在温和的条件下发生。当使用相对不活泼的亲二烯体如环戊烯和环己烯时,该反应需要苛刻的反应条件和/或路易斯酸催化剂。相反,用于分子内反应的模型表明即使在不存在路易斯酸催化剂的情况下,环加成反应也在室温下在数小时内发生。从这些结果得出的结论与上述代谢物的生物合成有关。