Divinylcarbinols 17 and 18, CS-symmetrical and cis-configured, were desymmetrized by Sharpless’ asymmetric epoxidation. This furnished anti-configured monoepoxy alcohols 19 (85% ee) and 20 (94% ee), respectively, or their mirror images (ent-19, 84% ee; ent-20, 95% ee). 20 (ent-20) was reduced by Red-Al® regio- and chemoselectively, providing syn-1,3-diols ent-21 (21) at low and ent-22 (22) at higher temperature (94-95% ee). They should allow the obtention of more elaborated syn-1,3-diols.
二
乙烯基甲醇 17 和 18 具有 CS 对称性和顺式构型,通过 Sharpless 不对称环氧化反应进行去对称化。这分别生成了反构型单环氧醇 19(85%ee)和 20(94%ee)或它们的镜像(ent-19,84%ee;ent-20,95%ee)。20(ent-20)被 Red-Al® 进行了区域和
化学选择性还原,在低温下生成了合成 1,3 二醇 ent-21 (21),在高温下生成了合成 1,3 二醇 ent-22 (22)(94-95%ee)。它们应该可以得到更精细的合成-1,3
-二醇。