Pd0‐Catalyzed Asymmetric Carbonitratation Reaction Featuring an H‐Bonding‐Driven Alkyl−PdII−ONO2 Reductive Elimination

Abstract

AbstractReductive elimination of alkyl−PdII−O is a synthetically useful yet underdeveloped elementary reaction. Here we report that the combination of an H‐bonding donor [PyH][BF4] and AgNO3 additive under toluene/H2O biphasic system can enable such elementary step to form alkyl nitrate. This results in the Pd0‐catalyzed asymmetric carbonitratations of (Z)‐1‐iodo‐1,6‐dienes with (R)‐BINAP as the chiral ligand, affording alkyl nitrates up to 96 % ee. Mechanistic studies disclose that the reaction consists of oxidative addition of Pd0 catalyst to vinyl iodide, anion ligand exchange between I− and NO3−, alkene insertion and SN2‐type alkyl−PdII−ONO2 reductive elimination. Evidences suggest that H‐bonding interaction of PyH⋅⋅⋅ONO2 can facilitate dissociation of O2NO− ligand from the alkyl−PdII−ONO2 species, thus enabling the challenging alkyl−PdII−ONO2 reductive elimination to be feasible.