Department of Chemistry, University of Minnesota Twin Cities , Minneapolis, Minnesota 55455, United States.
J Am Chem Soc. 2017 Jun 14;139(23):7737-7740. doi: 10.1021/jacs.7b04203. Epub 2017 Jun 5.
The catalytic enantioselective preparation of densely functionalized amines is a fundamental synthetic challenge. To address this challenge, we report for the first time that the Winstein rearrangement can be enlisted as the racemization pathway in a dynamic kinetic resolution of allylic azides. Alkene functionalization by Sharpless dihydroxylation affords tertiary azides in excellent enantioselectivity (up to 99:1 er). This approach establishes the chirality of the tertiary azide, obviates the need to directly forge either a congested C-N or C-C bond at the new nitrogenous stereocenter, and establishes additional functionality. Several examples demonstrate further elaboration of this functionality.
手性的、高度官能化胺的催化对映选择性制备是一项基本的合成挑战。为了解决这一挑战,我们首次报道,Winstein 重排可以作为动态动力学拆分烯丙基叠氮化物的外消旋化途径。烯烃经 Sharpless 双羟化反应得到的三级叠氮化物具有优异的对映选择性(高达 99:1 er)。这种方法确定了三级叠氮化物的手性,避免了在新的含氮立体中心直接形成拥挤的 C-N 或 C-C 键的需要,并建立了额外的功能。几个例子进一步展示了这种功能的进一步阐述。