Pd<sup>0</sup>‐Catalyzed Asymmetric Carbonitratation Reaction Featuring an H‐Bonding‐Driven Alkyl−Pd<sup>II</sup>−ONO<sub>2</sub> Reductive Elimination
Linjun Qi, Ming Dong, Jinlong Qian, Shuling Yu, Xiaofeng Tong
Abstract
Abstract Reductive elimination of alkyl−Pd II −O is a synthetically useful yet underdeveloped elementary reaction. Here we report that the combination of an H‐bonding donor [PyH][BF 4 ] and AgNO 3 additive under toluene/H 2 O biphasic system can enable such elementary step to form alkyl nitrate. This results in the Pd 0 ‐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 Pd 0 catalyst to vinyl iodide, anion ligand exchange between I − and NO 3 − , alkene insertion and S N 2‐type alkyl−Pd II −ONO 2 reductive elimination. Evidences suggest that H‐bonding interaction of PyH⋅⋅⋅ONO 2 can facilitate dissociation of O 2 NO − ligand from the alkyl−Pd II −ONO 2 species, thus enabling the challenging alkyl−Pd II −ONO 2 reductive elimination to be feasible.