Snider Barry B, Zhou Jingye
Department of Chemistry, MS 015, Brandeis University, Waltham, Massachusetts 02454-9110, USA.
Org Lett. 2006 Mar 30;8(7):1283-6. doi: 10.1021/ol052948+.
[reaction: see text] The synthesis of (+)-Sch 642305 (1) has been completed in 17 steps in 1.6% overall yield. Transannular Michael reaction of 2b with NaH in THF provided cyclohexenone 23 stereospecifically. Heating 23 in TFA/CDCl(3) provided a 3:1 equilibrium mixture of 23 and 25, which was hydrolyzed to give (+)-6-epi-Sch 642305 (24) and (+)-Sch 642305 (1), respectively.
[反应:见正文] (+)-Sch 642305(1)的合成已通过17步完成,总产率为1.6%。2b与NaH在四氢呋喃中进行跨环迈克尔反应,立体定向地生成环己烯酮23。在三氟乙酸/氘代氯仿中加热23,得到23和25的3:1平衡混合物,将其水解分别得到(+)-6-表-Sch 642305(24)和(+)-Sch 642305(1)。