Boron Lewis Acid Extraction of Wood Generates High Quality Lignin.

The separation of lignocellulose into lignin, cellulose, and hemicellulose without significantly altering the chemical structures of these component biopolymers remains a modern chemical challenge. Lignin, in particular, has potential as a highly valuable feedstock material but remains underutilized due to the difficulty of generating lignin with low modification and condensation. This work investigates the lignin-rich solids ("boron lignin") generated from a previously reported boron Lewis acid-mediated lignocellulose separation and concludes that (1) boron Lewis acid extraction removes 80-85% of carbohydrates from the original lignocellulose sample, and (2) the resulting lignin possesses a low condensation level and high similarity to native lignin structure.

Boron Triiodide-Mediated Reduction of Nitroarenes Using Borohydride Reagents.

The reduction of nitroarenes using KBH and I is described. BI is generated in situ and was shown to be the active reductant. Conditions were optimized for BI generation and then applied to a wide range of nitroarenes, including traditionally challenging substrates.

Structure-activity relationship and bioactivity studies of neurotrophic -banglene.

The synthesis and bioactivity of neurotrophic banglenes and derivatives is described, establishing a structure-activity relationship which enables future mechanistic studies. Neuritogenesis assays indicate that (-) -banglene is the active enantiomer. Assays performed with and without NGF protein suggest that neurotrophic activity and potentiation of NGF activity by (-) -banglene might be distinct unassociated processes.

Iron-Catalyzed Halogen Exchange of Trifluoromethyl Arenes*.

The facile production of ArCF X and ArCX from ArCF using catalytic iron(III)halides is reported, which constitutes the first iron-catalyzed halogen exchange for non-aromatic C-F bonds. Theoretical calculations suggest direct activation of C-F bonds by iron coordination. ArCX and ArCF X products of the reaction are synthetically valuable due to their diversification potential.

pH Dependence of the OH Reactivity of Organic Acids in the Aqueous Phase.

Photochemical processing taking place in atmospheric aqueous phases serves as both a source and a sink of organic compounds. In aqueous environments, acid-base chemistry and, by extension, aqueous-phase pH, are an important yet often neglected factors to consider when investigating the kinetics of organic compounds. We have investigated the aqueous-phase OH-oxidation of pinic acid, pinonic acid, limononic acid, and formic acid (FA) as a function of pH.

Reliably Regioselective Dialkyl Ether Cleavage with Mixed Boron Trihalides.

A protocol for the regioselective cleavage of unsymmetrical alkyl ethers to generate alkyl alcohol and alkyl bromide products is described. A mixture of trihaloboranes triggers this conversion and exhibits improved reactivity profiles (regioselectivity and yield) compared with BBr alone. Additionally, this procedure allows the efficient synthesis of (B-Cl) dialkyl boronate esters.

A Fluorescent Sensor and Gel Stain for Detection of Pyrophosphorylated Proteins.

The design and synthesis of a fluorescent sensor of diphosphate esters along with its application for in-gel detection is described. Dinuclear zinc complex 1 selectively binds diphosphate esters in the presence of various other functional groups, including monophosphate esters. Complex 1 also constitutes a competent stain for visualization of pyrophosphorylated proteins in polyacrylamide gels.

Traceless directing group for stereospecific nickel-catalyzed alkyl-alkyl cross-coupling reactions.

Stereospecific nickel-catalyzed cross-coupling reactions of benzylic 2-methoxyethyl ethers are reported for the preparation of enantioenriched 1,1-diarylethanes. The 2-methoxyethyl ether serves as a traceless directing group that accelerates cross-coupling. Chelation of magnesium ions is proposed to activate the benzylic C-O bond for oxidative addition.

Rhodium-catalyzed redox allylation reactions of ketones.

Ketones react with allyl acetate to generate tertiary homoallylic alcohols in the presence of a rhodium catalyst and bis(pinacolato)diboron. A range of substrates, including aryl, alkyl and cyclic ketones react smoothly under these conditions. Diastereoselective allylation reactions of functionalized ketones such as pregnenolone acetate are also reported.