8 research outputs found
Direct Conversion of Carboxylic Acids to Alkyl Ketones
An
efficient and mild method for acyl–C<sub>sp3</sub> bond
formation based on the direct conversion of carboxylic acids has been
established. This protocol is enabled by the synergistic, Ir-photoredox/nickel
catalytic cross-coupling of in situ activated carboxylic acids and
alkyltrifluoroborates. This versatile method is amenable to the cross-coupling
of structurally diverse carboxylic acids with various potassium alkyltrifluoroborates,
affording the corresponding ketones with high yields. In this operationally
simple cross-coupling protocol, aliphatic ketones are obtained in
one step from bench stable, readily available carboxylic acids
Synergistic Photoredox/Nickel Coupling of Acyl Chlorides with Secondary Alkyltrifluoroborates: Dialkyl Ketone Synthesis
Visible
light photoredox/nickel dual catalysis has been employed
in the cross-coupling of acyl chlorides with potassium alkyltrifluoroborates.
This protocol, based on single-electron-mediated alkyl transfer, circumvents
the restriction of using reactive alkylmetallic nucleophiles in transition-metal-catalyzed
acylation and achieves a mild and efficient method for the synthesis
of unsymmetrical alkyl ketones. In this approach, a variety of acyl
chlorides have been successfully coupled with structurally diverse
potassium alkyltrifluoroborates, generating the corresponding ketones
with good yields
Toward Efficient Nucleophilic Azaborine Building Blocks for the Synthesis of B–N Naphthyl (Hetero)arylmethane Isosteres
To develop a method for the synthesis
of a class of azaborines,
potassium 2-(trifluoroboratomethyl)-2,1-borazaronaphthalenes have
been synthesized to serve as nucleophilic building blocks. In palladium-catalyzed
cross-coupling reactions with (hetero)Âaryl chlorides they serve to
produce a variety of pseudobenzylic (hetero)Âaryl substituted azaborines.
Potassium 2-(trifluoroboratomethyl)-2,1-borazaronaphthalenes are crystalline
solids that are more stable than 2-(chloromethyl)-2,1-borazaronaphthalenes
and have a broader substrate scope in cross-coupling reactions compared
to their pseudobenzylic chloride counterparts
Visible Light Photoredox Cross-Coupling of Acyl Chlorides with Potassium AlkoxyÂmethylÂtrifluoroÂborates: Synthesis of α‑Alkoxyketones
A visible-light,
single-electron-transfer (SET), photoredox cross-coupling
for the synthesis of α-alkoxyketones has been developed. In
this method, various aliphatic and aromatic acyl chlorides were successfully
coupled with structurally diverse potassium alkoxyÂmethylÂtrifluoroÂborates,
producing the corresponding α-alkoxyketones with high yields.
In this operationally simple and mild cross-coupling protocol, the
desired ketones are obtained in one step from bench stable starting
materials by a bond connection that is unique to both alkylboron chemistry
and photoredox/Ni catalysis
Single-Electron Transmetalation: Photoredox/Nickel Dual Catalytic Cross-Coupling of Secondary Alkyl β‑TrifluoroÂboratoÂketones and -esters with Aryl Bromides
The
first cross-coupling of secondary alkyl β-trifluoroÂboratoÂketones
and -esters has been achieved through application of photoredox/nickel
dual catalysis. Although the related β-trifluoroÂboratoÂamides
have been effectively cross-coupled via Pd-catalysis, the corresponding
ketones and esters had proven recalcitrant prior to this report. Reactions
occur under mild conditions, and a variety of functional groups and
sterically and electronically diverse reaction partners are tolerated
Accessing an Azaborine Building Block: Synthesis and Substitution Reactions of 2‑ChloroÂmethyl-2,1-borazaroÂnaphÂthalene
One
major synthetic route to the synthesis of benzyl amines, ethers,
and esters is the nucleophilic substitution of a benzylic halide.
To develop a method for the facile synthesis and functionalization
of the isosteric azaborines, 2-chloroÂmethyl-2,1-borazaroÂnaphÂthalene
has been synthesized in one step to afford a similar common precursor
to a benzylic halide. This B–N isostere has been shown to be
an effective building block by serving as an electrophile in substitution
reactions with a large variety of nucleophiles
Accessing 2‑(Hetero)arylmethyl‑, -allyl‑, and -propargyl-2,1-borazaronaphthalenes: Palladium-Catalyzed Cross-Couplings of 2‑(Chloromethyl)-2,1-borazaronaphthalenes
The
synthesis of 2-(chloromethyl)-2,1-borazaronaphthalene has provided
an opportunity to expand dramatically the functionalization of the
azaborines. This azaborinyl building block can serve as the electrophile
in palladium-catalyzed cross-coupling reactions to form sp<sup>3</sup>–sp and sp<sup>3</sup>–sp<sup>2</sup> bonds. The cross-coupling
reactions of 2-(chloromethyl)-2,1-borazaronaphthalene with potassium
(hetero)Âaryl- and alkenyltrifluoroborates as well as terminal alkynes
provides access to a variety of novel azaborines, allowing a library
of pseudobenzylic substituted azaborines to be prepared from one common
starting material