Department of Chemistry , University of Pittsburgh , Pittsburgh , Pennsylvania 15260 , United States.
Org Lett. 2019 Jul 5;21(13):5064-5067. doi: 10.1021/acs.orglett.9b01660. Epub 2019 Jun 20.
Ketones that are flanked by an allylic alcohol and an alkene isomerize to spirocyclic ethers in the presence of ReO through allylic alcohol transposition, oxocarbenium ion formation, and Prins cyclization. These processes provide significant increases in molecular complexity, with multiple stereocenters being set relative to a stereocenter in the substrate. Stereoselectivity arises from the initial reversible steps being more rapid than the final step, thereby allowing for thermodynamically controlled stereochemical equilibration prior to product formation.
在 ReO 的存在下，被烯丙基醇和烯烃包围的酮通过烯丙基醇移位、氧杂碳正离子形成和 Prins 环化反应异构化为螺环醚。这些过程显著增加了分子的复杂性，相对于底物中的一个立体中心，生成了多个立体中心。立体选择性源于初始可逆步骤比最终步骤更快，从而允许在形成产物之前进行热力学控制的立体化学平衡。
