Substituent effect on benzylic lithiation of sulfides. Synthesis of diboronic acids derived from aryl–alkyl sulfides

Engineering of Solvatomorphs of the Luminescent Complex of ortho-Phenylenediboronic Acid and 8-Hydroxyquinoline

“…To date, organoboron compounds have found many applications in diverse areas of chemistry (organic synthesis, catalysis), biology (membrane transport), and medicine (supramolecular receptors, enzyme inhibitors, boron neutron capture therapy agents) . Additionally, some of them, as, e.g., four-coordinated organoboron complexes with chelating (N,O), (N,N), or (N,C) rigid π-conjugated ligands, can be used in materials science as organic light-emitting diodes (OLEDs), thanks to their bright luminescence, − while some others, such as phenylenediboronic acids, are of particular interest in crystal engineering due to their ability to form complex hydrogen-bonded networks, − or more recently reported and explored triphenylboroxine, creating various B–N-bonded molecular patterns depending on the solvent used . Furthermore, a number of boronic acids exhibit extremely low toxicity when compared to many other organic compounds; thus they are readily used as components of pharmaceuticals.…”

Regioselective lithiation of 1‐benzylpyrazole derivatives: Synthesis of amides derived from pyrazole

“…Our former studies on competitive benzylic lithiation of arylbenzyl sulfides revealed that bromine atom in the ortho position of the benzylic system accelerates deprotonation by a factor of 22.1 when compared to an unsubstituted phenyl ring. [23] We believe that the electron-withdrawing effect of the bromine atom in 3 is responsible for the stabilization of the benzyllithium derivative towards isomerization. Similar results were obtained upon lithiation-slilylation of the meta and para isomers 4 and 5 where we obtained selectively 4a and SCHEME 1 Deprotonative lithiation of 9 using LDA FIGURE 1 Labelling of atoms and estimation of their atomic thermal motion as anisotropic displacement parameters (ADPs, 50% probability level) for two symmetrically non-equivalent molecules for 9a 5a.…”

“…Interestingly, sequential lithiation–silylation of 3 with LDA/Me 3 SiCl in THF at −78 °C resulted in benzylic deprotonation affording 3a and unreacted 3 (0.9/1). Our former studies on competitive benzylic lithiation of arylbenzyl sulfides revealed that bromine atom in the ortho position of the benzylic system accelerates deprotonation by a factor of 22.1 when compared to an unsubstituted phenyl ring . We believe that the electron‐withdrawing effect of the bromine atom in 3 is responsible for the stabilization of the benzyllithium derivative towards isomerization.…”

Ground-State Charge-Density Distribution in a Crystal of the Luminescent ortho-Phenylenediboronic Acid Complex with 8-Hydroxyquinoline

“…Since the early 1980s arylboronic acids and their derivatives have been attracting increasing attention thank to wide applications in organic synthesis and medicine . Today, these compounds are also of particular interest in crystal engineering due to their abilities to form complex hydrogen-bonded networks. − Additionally, they exhibit promising properties regarding supramolecular − and materials chemistry. − For instance, diarylborinic compounds, described by a general formula Ar 2 BX (X = Cl, OH, OR), can be easily complexed with various (N,O), (N,N), or (N,C) rigid π-conjugated ligands, leading to luminescent 4-coordinated organoboron systems. − This enables their wide use in the construction of optical and optoelectronic devices, including organic light-emitting diodes (OLEDs), organic field-effect transistors (OFETs), and photoresponsive materials. − Specifically, 8-oxyquinolinato complexes are among the most promising compounds in this context. − This is presumably due to their high stability and good photophysical properties, such as high quantum yields and charge-transport properties.…”