XXX.—A rule for determining whether a given benzene mono-derivative shall give a meta-di-derivative or a mixture of ortho- and para-di-derivatives

Abstract

WHEN a monobenzene derivative CsHSX is so treated as t o give a dibenzene derivative C6H4XY, it is well known that, as a rule, this dibenzene derivative is either ( a ) exclusively, or nearly so, a mefa-.compound, or ( b ) a mixture of ortho-and parawith none o r very little 2 u 2

Integrating Metal-Catalyzed C–H and C–O Functionalization To Achieve Sterically Controlled Regioselectivity in Arene Acylation

“…31−38 In Friedel− Crafts reactions, electron-donating groups (EDGs) direct acylation to the ortho and para positions, in many cases producing a mixture of products (Figure 2a). 39 Single-site acylation via metal-catalyzed C−H functionalization is typically achieved using a covalently attached or transient directing group (DG) (Figure 2b). [28][29][30]40,41 DGs permit acylation primarily at the ortho position (within the regioselectivity purview of Friedel−Crafts acylation), but meta selectivity is also known.…”

Synthesis of Polycyclic Aromatic Hydrocarbons by Phenyl Addition–Dehydrocyclization: The Third Way

“…The initial replacement of a hydrogen atom by a phenyl group in the biphenyl reactant represents a prototype of an aromatic radical substitution reaction (S R ). This reaction favors the addition of the radical reactant to the o ‐ and p ‐position of the phenyl moiety followed by atomic hydrogen loss leading to o ‐ and p ‐terphenyl, but not to m ‐terphenyl. The p ‐terphenyl was observed experimentally; the absence of o ‐terphenyl, but the identification of triphenylene suggests an efficient conversion through dehydrogenation and cyclization of o ‐terphenyl to triphenylene (Figure ) thus demonstrating the unique capability of PAC to synthesize triphenylene.…”

In Situ Assessment of Intrinsic Strength of X-I⋯OA-Type Halogen Bonds in Molecular Crystals with Periodic Local Vibrational Mode Theory

“…One also needs to consider the substituent effects of the -N(CH 3 ) 2 amine group linked to an aromatic ring. As it is well-known that amine group has an ortho-/para-directing effect for electrophilic aromatic substitution reactions [130][131][132][133], so the nitrogen atom of the N + -O − bond in the para position with regard to the amine group in acceptor O can attract more electron density from the aromatic ring while loosening the attraction of the NO bonding electrons. Therefore, the oxygen atom of the N + -O − bond can accumulate electron density via its large electronegativity.…”