1,5-Disubstituted-2,4-pentadiynyl silyl ethers undergo smooth desilylative isomerization to afford cis-enynones as major products with moderate stereoselectivities in the presence of a catalytic amount of KO(t)Bu or DBU. While the isomerization reactions of their alcohol derivatives catalyzed by KOH, KO(t)Bu or NaH take place efficiently to produce trans-enynones with high stereoselectivities. ...

Results of a series of hybrid quantum mechanical/molecular mechanical (QM/MM) activated dynamics simulations of thio effects in the transphosphorylation (methanolysis) of a 2'-ribose, 5'-methyl phosphate-diester under basic conditions are presented. Single and double substitutions in the nonbridging oxygen positions exhibit thio effects in accord with experimental data and show the existence of...

We report asymmetric allylic alkylation of barium enolates of cyclic ketones catalyzed by a metallacyclic iridium complex containing a phosphoramidite ligand derived from (R)-1-(2-naphthyl)ethylamine. The reaction products contain adjacent quaternary and tertiary stereocenters. This process demonstrates that unstabilized cyclic ketone enolates can undergo diastereo- and enantioselective Ir-cata...

Abstract Organolithium compounds have been used successfully in flow chemistry since the recent past. Most of studies dealt with use halogen-lithium exchanges. So far, however, there has a lack substitution reactions. The microreactors makes highly reactive organolithium more controllable and thus creates new synthetic possibilities.

The scope of the [4 + 2] cycloaddition reactions of substituted 1,2,3-triazines, bearing noncomplementary substitution with electron-withdrawing groups at C4 and/or C6, is described. The studies define key electronic and steric effects of substituents impacting the reactivity, mode (C4/N1 vs C5/N2), and regioselectivity of the cycloaddition reactions of 1,2,3-triazines with amidines, enamines, ...

The effect of substitution on boron in the Diels-Alder reactions of vinylboranes has been investigated by a computational study performed with the B3LYP/6-31G* method. Four vinylboranes with different electronic and steric properties were chosen to study the reactivity and the regioand stereoselectivities patterns. In general, the calculations for the reactions with cyclopentadiene, trans-piper...

Photoinduced nucleophilic substitution reactions of thirty p-nitrodiphenyl ethers including the herbicides nitrofen and chlornitrofen with a variety of amines were examined. The reaction took place by liberating nitrophenoxide or nitrite, depending on the substituents. Nitrofen liberated mainly nitrophenoxide by reactions with pyridine and 4methylpyridine to give N-phenylpyridinums, whereas chl...

Three perhalogenated BODIPYs (1b-3b), bearing chloro and bromo groups at all carbon positions, were synthesized and characterized. The reactivity of BODIPY 3b was investigated under Stille cross-coupling reactions, and single crystal X-ray analysis was used to confirm the regioselectivity of the reactions. Further substitution at the boron atom produced nona-functionalized BODIPYs 7a,b, which s...

The photostimulated reaction of Me3Sn ion with mono, di and trichloro arenes in liquid ammonia gave very good yields of stannanes by the SRN1 mechanism. These products reacted by a palladium-catalized cross coupling reaction with halobenzenes to give phenylated products also in very goods yields. Similar yields can be obtained in one-pot reactions. Introduction The radical nucleophilic substitu...

With the increasing concern for sustainability, the use of environmentally friendly media to perform chemical processes has attracted the attention of many research groups. Among them, the use of water, as the unique solvent for reactions, is currently an active area of research. One process of particular interest is the direct nucleophilic substitution of an alcohol avoiding its preliminary tr...