Concise Six-Step Asymmetric Approach to Ramelteon from an Acetophenone Derivative Using Ir, Rh, Cu, and Ni Catalysis
作者:Jérôme Cluzeau、Ulrike Nettekoven、Miroslav Planinc Kovačevič、Zdenko Časar
DOI:10.1021/acs.joc.1c01614
日期:2022.2.18
asymmetric synthesis of nearly enantiomerically pure ramelteon was developed from a monocyclic precursor with a 17% overall yield and a 97% ee in the asymmetric step. The synthetically challenging tricyclic 1,6,7,8-tetrahydro-2H-indeno[5,4-b]furan core of ramelteon was assembled by using Ir-catalyzed O-vinylation and Rh-catalyzed vinyl ether annulation through directed C–H bond activation, while the
从单环前体开发了一种简洁的六步不对称合成几乎对映体纯的 ramelteon,在不对称步骤中总产率为 17%,ee 为 97%。具有合成挑战性的三环 1,6,7,8-四氢-2 H-茚并[5,4- b ]呋喃核心是通过使用 Ir 催化的O -乙烯基化和 Rh 催化的乙烯基醚环化通过定向 C– H键活化,而手性通过使用Cu II /Walphos型催化剂在氢化硅烷化条件下对映选择性还原α,β-不饱和腈部分来引入。所提出的方法代表了 ramelteon 的最短合成方法。