Xu Bin, Gartman Jackson, Tambar Uttam K
Department of Biochemistry, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390-9038, United States.
Tetrahedron. 2017 Jul 20;73(29):4150-4159. doi: 10.1016/j.tet.2017.01.048. Epub 2017 Jan 25.
The [1,2]- and [2,3]-rearrangements of iodonium ylides are synthetically useful reactions for the generation of functionalized α-iodoesters. Allylic iodides are coupled with α-diazoesters in the presence of a copper catalyst and a ligand to generate iodonium ylides, which undergo metal-mediated rearrangements. By fine-tuning the structure of the ligand, we have reversed the regioselectivity of copper-catalyzed reactions of iodonium ylides from [2,3]- to [1,2]-rearrangements with the use of alternate bipyridine ligands. The preference for [1,2]-rearrangements was further improved by using bulky aryl α-diazoester substrates. Several α-iodoesters with a diverse range of functional groups were generated in good yields (up to 88% yield) and high regioselectivities (up to >95:5 regioisomeric ratio). A deuterium-labeled substrate was utilized to gain insight into the mechanism of the reaction.
碘鎓叶立德的[1,2]-和[2,3]-重排反应是合成功能化α-碘代酯的有用反应。烯丙基碘化物在铜催化剂和配体存在下与α-重氮酯偶联生成碘鎓叶立德，其发生金属介导的重排反应。通过微调配体的结构，我们使用交替的联吡啶配体将碘鎓叶立德的铜催化反应的区域选择性从[2,3]-重排反转至[1,2]-重排。通过使用庞大的芳基α-重氮酯底物，对[1,2]-重排的偏好性进一步提高。以良好的产率（高达88%产率）和高区域选择性（高达>95:5区域异构体比例）生成了几种具有多种官能团的α-碘代酯。使用氘标记的底物来深入了解反应机理。
