Chromium‐Catalyzed Selective Dimerization/Hydroboration of Allenes to Access Boryl‐Functionalized Skipped (<i>E</i>,<i>Z</i>)‐Dienes
Yinsong Zhao, Shaozhong Ge
Abstract
Abstract A chromium‐catalyzed dimerization/hydroboration of allenes is developed to access synthetically versatile boryl‐functionalized skipped dienes with a catalyst generated in situ from CrCl 2 and a pyridine‐2,6‐diimine ligand mes PDI. A variety of allenes reacted with pinacolborane (HBpin) to afford the corresponding boryl‐functionalized ( E , Z )‐1,4‐dienes in high yields and with excellent selectivity. Electron paramagnetic resonance (EPR) spectroscopic studies suggest that this chromium‐catalyzed reaction probably proceeds through a chromium(I) hydride intermediate.
Topics & Concepts
HydroborationChemistryChromiumCatalysisElectron paramagnetic resonancePyridineHydrideSelectivityMedicinal chemistryLigand (biochemistry)Organic chemistryPhotochemistryMetalBiochemistryReceptorPhysicsNuclear magnetic resonanceOrganoboron and organosilicon chemistryCatalytic Cross-Coupling ReactionsCatalytic C–H Functionalization Methods