Microbiota Modulate Behavioral and Physiological Abnormalities Associated with Neurodevelopmental Disorders

The ternary system consisting of [RuCl2(η6-benzene)]2, N-tosylethylenediamine or ethanolamine, and KOH (Ru:amine:KOH = 1:1:2 molar ratio) catalyzes reversible hydrogen transfer between alcohols and carbonyl compounds. The use of chiral amine auxiliaries effects asymmetric transformation. The theoretical calculations using methanol/formaldehyde transformation as the model indicates the operation of a novel metal−ligand bifunctional catalysis, which is contrary to currently accepted putative pathways. The results reveal that:  (1) KOH is necessary for the generation of a formal 16-electron Ru complex, Ru(NHCH2CH2Y)(η6-benzene) (Y = O or NH) (catalyst), from an 18-electron Ru chloride, RuCl(NH2CH2CH2Y)(η6-benzene) (precatalyst), by a Dcb elimination of HCl, and not for increasing alkoxide concentration; (2) Ru alkoxides do not intervene in transfer hydrogenation; (3) the Ru alkoxide, even if formed, serves merely as a reservoir of the 16-electron catalyst; (4) the key 18-electron Ru hydride, RuH(NH2CH2CH2Y)(...

The Metal−Ligand Bifunctional Catalysis: A Theoretical Study on the Ruthenium(II)-Catalyzed Hydrogen Transfer between Alcohols and Carbonyl Compounds

Aryl sulfonyl chlorides (e.g. Ts-Cl) are beloved of organic chemists as the most commonly used S(VI) electrophiles, and the parent sulfuryl chloride, O2 S(VI) Cl2 , has also been relied on to create sulfates and sulfamides. However, the desired halide substitution event is often defeated by destruction of the sulfur electrophile because the S(VI) Cl bond is exceedingly sensitive to reductive collapse yielding S(IV) species and Cl(-) . Fortunately, the use of sulfur(VI) fluorides (e.g., R-SO2 -F and SO2 F2 ) leaves only the substitution pathway open. As with most of click chemistry, many essential features of sulfur(VI) fluoride reactivity were discovered long ago in Germany.6a Surprisingly, this extraordinary work faded from view rather abruptly in the mid-20th century. Here we seek to revive it, along with John Hyatt's unnoticed 1979 full paper exposition on CH2 CH-SO2 -F, the most perfect Michael acceptor ever found.98 To this history we add several new observations, including that the otherwise very stable gas SO2 F2 has excellent reactivity under the right circumstances. We also show that proton or silicon centers can activate the exchange of SF bonds for SO bonds to make functional products, and that the sulfate connector is surprisingly stable toward hydrolysis. Applications of this controllable ligation chemistry to small molecules, polymers, and biomolecules are discussed.

Sulfur(VI) Fluoride Exchange (SuFEx): Another Good Reaction for Click Chemistry

Asymmetric transfer hydrogenation of C=O and C=N bonds

The sulfonation (also known as sulfurylation) of biomolecules has long been known to take place in a variety of organisms, from prokaryotes to multicellular species, and new biological functions continue to be uncovered in connection with this important transformation. Early studies of sulfotransferases (STs), the enzymes that catalyze sulfonation, focused primarily on the cytosolic STs, which are involved in detoxification, hormone regulation, and drug metabolism. Although known to exist, the membrane-associated STs were not studied as extensively until more recently. Involved in the sulfonation of complex carbohydrates and proteins, they have emerged as central players in a number of molecular-recognition events and biochemical signaling pathways. STs have also been implicated in many pathophysiological processes. As a result, much interest in the complex roles of STs and in their targeting for therapeutic intervention has been generated. Progress in the elucidation of the structures and mechanisms of sulfotransferases, as well as their biological activity, inhibition, and synthetic utility, are discussed in this Review.

Vernon J. Shiner

Papers

Stable chlorine and carbon isotopic compositions of selected semi-volatile organochlorine compounds

Solvolysis rates and deuterium isotope effects in 2,2,2-trifluoroethanol-- water mixtures.

$alpha$-DEUTERIUM EFFECTS ON THE RATES OF SOLVOLYSIS OF A 2-ADAMANTYL SULFONATE ESTER.

Kinetics of the Meerwein-Ponndorf-Verley reaction

Enhancement of Solvolysis Rates by Wagner-Meerwein Rearrangements of Ion Pairs