Nickel-Catalyzed Arylation/Alkenylation of tert-Cyclobutanols with Aryl/Alkenyl Triflates via a CC Bond Cleavage

Synergistic use of photocatalysis and convergent paired electrolysis for nickel-catalyzed arylation of cyclic alcohols

The merging of transition metal catalysis with electrochemistry has become a powerful tool for organic synthesis because catalysts can govern the reactivity and selectivity. However, coupling catalysts with alkyl radical species generated by anodic oxidation remains challenging because of electrode passivation, dimerization, and overoxidation. In this study, we developed convergent paired electrolysis for the coupling of nickel catalysts with alkyl radicals derived from photoinduced ligand-to-metal charge-transfer of cyclic alcohols and iron catalysts, providing a practical method for site-specific and remote arylation of ketones. The synergistic use of photocatalysis with convergent paired electrolysis can provide alternative avenues for metal-catalyzed radical coupling reactions.

Aryl boronic acid-controlled divergent ring-contraction and ring-opening/isomerization reaction of tert-cyclobutanols enabled by nickel catalysis

In this work, we wish to present a nickel-catalyzed divergent ring-contraction and ring-opening/isomerization reaction of tert-cyclobutanols. The key to control these two different reaction pathways is to choose appropriate boronic acid, where the use of phenylboronic acid and pyrimidin-5-ylboronic acid enables a ring-contraction and ring-opening reaction/isomerization, respectively. Both cyclopropyl aryl methanones and 1-aryl butan-1-ones could be selectively obtained.

Deconstructive isomerization of azetidinols via C-C bond cleavage enabled by N-heterocyclic carbene (NHC) catalysis

Herein, we describe an N-heterocyclic carbene (NHC)-catalyzed deconstructive isomerization of azetidinols via an inert C-C bond cleavage. It provides a direct and supplementary pathway to access α-amino ketone and oxazol-2-one derivatives in moderate to good yields. DFT calculation supports the proposed mechanism in which NHC undergoes a concerted proton transfer and ring-opening process. This reaction features non-metal catalysis, simple reaction operation, excellent regioselectivity and gram-scale synthesis.

2-Pyridinylmethyl borrowing: base-promoted C-alkylation of (pyridin-2-yl)-methyl alcohols with ketones via cleavage of unstrained C(sp3)–C(sp3) bonds

2-Pyridinylmethyl Borrowing: Transition-metal-free 2-pyridinylmethyl borrowing C-alkylation of alcohols access to ketones is developed. This unstrained C(sp3)–C(sp3) bonds cleavage of unactivated alcohols avoids the use of transition metals.

Palladium-Catalyzed Asymmetric Cross-Coupling Reactions of Cyclobutanols and Unactivated Olefins

Transition-metal-catalyzed activations of carbon-carbons bonds of small strained rings have widespread applications in synthetic and medicinal chemistry. However, coupling reactions of cyclobutanols involving β-carbon elimination to construct C(sp³)-C(sp³) bonds have scarcely been developed. Here, we demonstrate a highly enantioselective Pd-catalyzed intermolecular C(sp³)-C(sp³) coupling reaction of a broad range of cyclobutanol derivatives and unactivated alkenes, allowing convenient access to a series of chiral benzene-fused cyclic compounds in a highly regio-, chemo-, and enantioselective manner.

Nickel-catalyzed cyclization of 1,7-enynes for the selective synthesis of dihydrocyclobuta[c]quinolin-3-ones and benzo[b]azocin-2-ones

We herein described a nickel-catalyzed cyclization of N-(o-ethynylaryl)acrylamides for the selective synthesis of dihydrocyclobuta[c]quinolin-3-ones and benzo[b]azocin-2-ones. The two varied products could be easily obtained by tuning the reaction temperature. This reaction features easy temperature-control, high efficiency, and gram-scale synthesis.

Nickel-catalyzed remote hydrosilylation of unconjugated enones with bulky triphenylsilane

Herein we describe a nickel-catalyzed remote hydrosilylation of unconjugated enones with bulky triphenylsilane. A range of Z-silyl enol ethers are obtained as major isomers due to the process of nickel triggered alkene isomerization. Notably, some specific alkyl silyl enol ethers can be prepared from this protocol, which are not easily accessed by the traditional strategy using a strong base and chlorosilane. This reaction features 100% atom economy, simple reaction conditions, and good yields.

Selective cine-arylation of tert-cyclobutanols with indoles enabled by nickel catalysis

In previous literature, tert-cyclobutanols are widely studied for C-C bond activation exclusively leading to the formation of ordinary γ-substituted ketones. Herein, we first report a nickel-catalyzed cine-arylation of tert-cyclobutanols with indoles to access β-aryl ketones with an unusual site-selectivity at the C3-position of tert-cyclobutanols. The reaction features earth-abundant nickel catalysis, excellent regioselectivity, high atom-economy, and broad substrate scope.