Biomimetic diels–alder cyclizations for the construction of the brevianamide, paraherquamide, sclerotamide, asperparaline and VM55599 ring systems
作者:Robert M Williams、Juan F Sanz-Cervera、Félix Sancenón、J.Alberto Marco、Kathleen M Halligan
DOI:10.1016/s0968-0896(98)00102-3
日期:1998.8
A potentially bio-mimetic Diels-Alder cyclization to construct the bicyclo[2.2.2] ring system common to the paraherquamides, marcfortines, sclerotamides, brevianamides, VM55599, and asperparaline is reported. Epi-deoxybrevianamide E (22) is converted into the corresponding lactim ether (23) and then oxidized with DDQ to provide an azadiene (24) which is tautomerized in the presence of base to azadiene
据报道,一种潜在的仿生Diels-Alder环化反应可构建对乙酰氨基甲酰胺,马卡福汀,硬核酰胺,灯盏花酰胺,VM55599和天冬酰胺所共有的双环[2.2.2]环系统。Epi-deoxybrevianamide E(22)转化为相应的内酰胺醚(23),然后用DDQ氧化得到氮杂二烯(24),在碱存在下将其互变异构成氮杂二烯25,氮杂二烯25自发环化成2:1。环加合物26和27的混合物。将这些环加合物依次依次转化为D,LC-19-表-短酰胺酰胺A(20)和D,L-短酰胺B(6)。[4 + 2]环加成的立体化学含义是在有关该家族生物合成的有效假设(尤其是VM55599)的背景下进行讨论的。