Antimicrobial algal metabolites of unusual structure. Concise synthesis of the highly oxygenated [4.4]spirononene dimethyl gloiosiphone A by ring expansion of dimethyl squarate
作者:Claudio F. Sturino、Pascale Doussot、Leo A. Paquette
DOI:10.1016/s0040-4020(97)90400-2
日期:1997.6
A synthesis of dimethyl gloiosiphone A (2) has been realized. The key step involves the boron trifluoride-catalyzed eliminative ring expansion of a 2′-(dimethoxymethyl)-1′-(cyclopenten-1′-yl)-4-hydroxy-2-cyclobuten-1-one, which was directly assembled by condensation of the appropriate cycloalkenyllithium with dimethyl squarate. Following arrival at spirocyclic diketone 17 in only two steps, the cyclopentenedione
已经实现了二甲基gloiosiphone A(2)的合成。关键步骤涉及三氟化硼催化的2'-(二甲氧基甲基)-1'-(环戊烯-1'-基)-4-羟基-2-环丁烯-1-酮的消除环扩展。适当的环烯基锂与方酸二甲酯缩合。仅在两个步骤中到达螺环二酮17后,对环戊二酮A环进行受控的还原去除一个羰基。随后将烯醇醚氧化为不饱和醛21为适当修饰B环中的α-羟基酮部分结构奠定了基础。合成材料的光谱性质与天然2相同。最初是作为外消旋体而被孤立的。