Nickel-Catalyzed Suzuki Cross Couplings with Unprotected Allylic Alcohols Enabled by Bidentate N-Heterocyclic Carbene (NHC)/Phosphine Ligands

Abstract

Cross couplings between simple allylic alcohols and aryl and vinyl boronic acids are efficiently catalyzed by nickel(0) catalysts and bidentate N-heterocyclic carbene/phosphine ligands. The bidentate nature of the ligand is shown to extend catalyst lifetime and enable high yields of the corresponding cross-coupling products. X-ray crystallography confirms the bidentate nature of the ligand scaffold. Multistep cross coupling-alkene/alkyne insertions reactions are also conducted and the bidentate nature of the substrate makes the pendant phosphine of the ligand unnecessary.

Transition-Metal-Catalyzed Suzuki–Miyaura-Type Cross-Coupling Reactions of π-Activated Alcohols

“…In 2018, Michaelis and co-workers used Ni-NHC/phosphine to catalyze the Suzuki-Miyaura-type cross-coupling reaction of allylic alcohols with arylboronate ester 113 (Scheme 16B). 28 The bidentate NHC/phosphine ligands L1-L4 provided superior results compared to bidentate phosphine, dppf, and NHC carbene IPr•HCl ligands. The bidentate phosphine/carbene nickel(II)-methallyl complex 115, which is the active catalyst, was isolated and its structure was confirmed by X-ray crystallography.…”

“…A nickel-catalyzed domino Suzuki-Miyaura-type cross-coupling-alkene/alkyne insertion reaction employing a Ni-NHC ligand catalyst system was reported by Michaelis and co-workers in 2018 (Scheme 21B). 28 It was proposed that the bidentate nature of alkynyl-substituted allylic alcohol substrate 140 itself accelerates the reaction by binding the alkyne to the nickel catalyst. Using a bidentate NHC/phosphine ligand that occupied the coordination site of the nickel gave only a moderate yield of the cyclization product (cf.…”

Access to 1,3‐Dinitriles by Enantioselective Auto‐tandem Catalysis: Merging Allylic Cyanation with Asymmetric Hydrocyanation

“…In this context, low cost and highly abundant nickel appears to be the ideal catalyst for these transformations . Nickel‐catalyzed Negishi cross‐couplings, Suzuki cross‐couplings, allylic aminations, and alkylations with unprotected allylic alcohols have been demonstrated. A nickel‐catalyzed cyanation reaction was reported by Rousseaux and co‐workers using allylic pivalate esters as electrophiles to access allylic nitriles (Scheme a) .…”

Indolylboronic Acids: Preparation and Applications

“…Selected examples show how chloro- [29], bromo- [30], bromoindolyl phosphate [31], and triflates [32] are all capable of coupling with boronic acids under mild reaction conditions. Yet, a wide variety of allylic alcohols [33], heterocyclic halides [34], bromoenol phosphates [35], sulfones [36], and sulfonates [37] have been used as electrophilic templates in reactions with indolylboronic acids under Suzuki-Miyaura reaction conditions involving, for example EvanPhos [38] and tri- tert -butylphosphine ligand [39], nickel [40], and rhodium [41] catalysts, as well as asymmetric transformations [42,43]. The abovementioned examples illustrate the practical application of the Suzuki-Miyaura reaction by means of both electrophilic and nucleophilic indolyl templates for the synthesis of substituted indoles.…”