Attempts to alkylate products from Birch reductions of derivatives of
podocarpic acid are reported. Attempted reductive silylation of ring C of
methyl 12-methoxypodocarpa-8,11,13-trien-19-oate (5) gives products of C4
ester reduction only. The enantiopure form of the bis(ethylene acetal) (15) of
19-norpodocarp-8-ene-3,12-dione, a potentially useful intermediate for
quassinoid synthesis, has been prepared from the ketone (34). Functionality at
C8 on the β-face has been successfully introduced by abnormal
Reimer–Tiemann reactions of podocarpic acid (2) and its 13-methyl
derivative (10). The saturated ketone (48) has been converted into an
α,β-unsaturated ketone (18) which has potential for introducing
functionality at C14.
报告了桦木还原荚果酸衍
生物的烷基化产物的尝试。
荚果酸衍
生物的烷基化产物的尝试。尝试对 C 环的
12-Methoxypodocarpa-8,11,13-trien-19-oate (5) 环 C 的还原
硅烷化尝试只得到了 C4
酯还原的产物。19-全蝎-8,11,13-
三烯-19-酸甲酯的对映体双(
乙烯缩醛)(15)
19-去甲多果-8-烯-3,12-二酮的对映体形式(15),是一种潜在的有用中间体,可用于
酮制备出了对映体形式的 19-去甲-8-烯-3,12-二酮(34)。在
面 C8 上的功能性已通过异常的
Reimer-Tiemann 反应,成功地引入了荚果酸(2)及其 13-甲基
衍
生物 (10)。饱和酮 (48) 已转化为一个
α,β-不饱和酮 (18),它有可能在 C14 处引入
C14 的官能团。