Ligand‐Enabled Ni^II‐Catalyzed Hydroxylarylation of Alkenes with Molecular Oxygen

Abstract

The use of molecular oxygen as the terminal oxidant in transition metal catalyzed oxidative process is an appealing and challenging task in organic synthetic chemistry. Here, we report a Ni‐catalyzed hydroxylarylation of unactivated alkenes enabled by a β‐diketone ligand with high efficiency and excellent regioselectivity employing molecular oxygen as the oxidant and hydroxyl source. This reaction features mild conditions, broad substrate scope and incredible heterocycle compatibility, providing a variety of β‐hydroxylamides, γ‐hydroxylamides, β‐aminoalcohols, γ‐aminoalcohols, and 1,3‐diols in high yields. The synthetic value of this methodology was demonstrated by the efficient synthesis of two bioactive compounds, (±)‐3′‐methoxyl citreochlorol and tea catechin metabolites M4.

Photoredox-Driven Three-Component Coupling of Aryl Halides, Olefins, and O2

“…Additionally, ortho -substitution was well tolerated with both mono- and disubstituted arenes ( 23 – 28 , 36–90%). Previous hydroxyarylations have limited utility in functionalizing heteroaryl species. − Under our XAT conditions, pyridines could be functionalized at the 2-, 3-, and 4-positions in moderate yields ( 29 – 31 , 42–76%). Additional heterocycles such as pyrazine 32 , thiophene 33 , and indole 34 all produced hydroxyarylated products in 51–62% yields.…”

“… 9 To date, only a few reports have described the aryl radical reactivity in the presence of O 2 . Such reported reactions require aryl hydrazines, 10 aryl diazoniums, 11 or aryl boronates 9d , 12 as aryl radical precursors and are often combined with stoichiometric metal reductants, limiting their synthetic utility. Prior to this study, no catalytic multicomponent hydroxyarylation of olefins with aryl halides and O 2 has been reported.…”