Facial-Selective Allylation of Methyl Ketones for the Asymmetric Synthesis of Tertiary Homoallylic Ethers
作者:Lutz F. Tietze、Sören Hölsken、Jens Adrio、Tom Kinzel、Christoph Wegner
DOI:10.1055/s-2004-829153
日期:——
The stereoselective allylation of methyl ketones is described to give tertiary homoallylic ethers, which can easily be transformed into homoallylic alcohols by a Birch reduction. Reaction of methyl ketones 4 with allylsilane 5 in the presence of the chiral TMS ether 3a and a catalytic amount of trifluoromethanesulfonic acid led to homoallylic ethers 6 in high yield with a selectivity of 9:1 to >20:1
描述了甲基酮的立体选择性烯丙基化得到叔均烯丙基醚,其可以通过Birch还原很容易地转化为均烯丙醇。在手性 TMS 醚 3a 和催化量的三氟甲磺酸存在下,甲基酮 4 与烯丙基硅烷 5 的反应以 9:1 至 >20:1 的选择性以高产率生成均烯丙基醚 6。TMS 醚 3a 是由廉价的扁桃酸通过四个步骤制备的,扁桃酸有两种对映异构体的形式。