Bis(cis-1-alkenyl)methanols 2a and b were monoepoxidized by a 1:1:1 mixture of R tert OOH, an optically active tartaric acid derivative, and a Zr(IV) alkoxide. This provided epoxy alcohols syn-1a,b with perfect diastereoselectivity. These compounds are the minor products of analogous Ti(IV)-mediated epoxidations. The ee of epoxy alcohol syn-1a was increased up to 99% when less enantioenriched material was overoxidized under the reaction conditions (→ up to 66% bisepoxy alcohol syn,syn-5).
双(顺式-1-烯基)
甲醇 2a 和 b 通过 R tert OOH、具有光学活性的
酒石酸衍
生物和 Zr(IV)烷氧化物的 1:1:1 混合物进行单环氧氧化。这样就得到了具有完全非对映选择性的环氧醇 syn-1a,b。这些化合物是类似的 Ti(IV)介导环氧化反应的次要产物。在反应条件下,当对映体富集程度较低的材料被过氧化时,环氧醇 syn-1a 的ee提高到 99%(双环氧醇 syn,syn-5 的ee高达 66%)。