functionalized β-vinylacyl anion equivalent with benzocyclobutenedione monoacetal, followed by methyl-lithium addition, yields a tricyclic structure having the requisite stereochemistry for elaboration to tetracyclines, as confirmed by a single crystal X-ray structure determination.
如通过单晶X射线结构测定所证实的那样,使官能化的β-
乙烯基乙酰基阴离子当量与苯并环
丁二酮单
缩醛反应,然后添加
甲基锂,产生具有精制成
四环素所必需的立体
化学的
三环结构。