New Access Routes to Privileged and Chiral Ligands for Transition‐Metal Catalyzed Hydrogen Autotransfer (Borrowing Hydrogen), Dehydrogenative Condensation, and Alkene Isomerization Reactions

Abstract A group of transition‐metal catalyzed hydrogen moving reactions , encompassing autotransfer (HAT; also called borrowing BH), dehydrogenative condensation (DHC) and alkene isomerization, displays high atom economy relies on widely available starting materials. Such have considerable potential for clean reaction design application in sustainable synthesis. With the aim to develop study synthetic applications title reactions, we set up access routes a toolbox structurally varied ligands pincer complexes some transition metals (cobalt, ruthenium, iridium) that are well established reactions. Ligand target structures, which often improved syntheses been found, encompass 6,6’‐dihydroxy‐2,2’‐bipyridine, 2(3‐hydroxyphenyl)pyridines (as backbones PCN pincers), 2(6‐methylpyridine‐2‐yl)pyridines PNN pincers) 2(3‐tolyl)pyridines pincers). To support research towards asymmetric versions prepared asymmetrically modified well‐established catalysts, including chiral, enantiopure Milstein ’s PNN‐ruthenium pincer, Kempe triazinyl‐diaminophosphanyl PNP‐iridium‐ or ‐cobalt pincers, Huang PCN‐iridium Grotjahn zipper complex. The strategy applied ‘chiral switching ’ relied replacing symmetric dialkylphosphine donor‐groups by dimenthylphosphine aryl(menthyl)phosphine donor units. resulting characterized, catalytic catalysts has exploratory model (transfer hydrogenation; diol lactone condensation; isomerization). Several designed will allow .