Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark.
College of Materials, Chemistry and Chemical Engineering, Hangzhou Normal University, 311121, Hangzhou, P. R. China.
Chemistry. 2022 Dec 20;28(71):e202202951. doi: 10.1002/chem.202202951. Epub 2022 Oct 27.
An unusual diastereodivergent stereoselective allylation reaction is presented. It consists of a palladium-catalyzed allylation reaction of an organocatalytically generated amino isobenzofulvene, where the diastereoselectivity is controlled by the electronic properties of a monodentate, achiral ligand on palladium. One major diastereoisomer is formed using triarylphosphines substituted with neutral or electron-donating substituents of the aryl group, while those with electron-withdrawing substituents favor the other diastereoisomer. The diastereoselectivity correlates with the Taft inductive parameter of substituents on the triarylphosphine ligand on palladium. The synergistic reaction involves both a catalytic secondary amine catalyst for the indene-aldehyde activation and the monodentate phosphine ligands on palladium, affording a highly enantioselective reaction with up to 98 % enantiomeric excess. Based on computational investigations, the role of the monodentate phosphine ligand on the diastereoselectivity is discussed.
呈现了一种非寻常的立体选择性的双烯丙基化反应。它由有机催化生成的氨基异苯并呋喃的钯催化烯丙基化反应组成，其中钯上的单齿手性配体的电子性质控制了立体选择性。使用三芳基膦，其中芳基上的取代基为中性或给电子取代基，形成主要的非对映异构体，而具有吸电子取代基的则有利于另一种非对映异构体。立体选择性与钯上三芳基膦配体取代基的 Taft 诱导参数相关。协同反应涉及用于茚醛激活的催化仲胺催化剂和钯上的单齿膦配体，从而提供具有高达 98%对映过量的高对映选择性反应。基于计算研究，讨论了单齿膦配体在立体选择性中的作用。
