The first example of transition-metal-catalyzed ortho/meta-selective dual C-H functionalizations of arenes in one reaction is described. In this transformation, ortho-C-H chlorination and meta-C-H sulfonation of 2-phenoxypyri(mi)dines were achieved simultaneously under catalysis by [Ru(p-cymene)Cl]. The other reactant, namely, an arylsulfonyl chloride, played the role of both a sulfonation and chlorination reagent. More importantly, the arylsulfonyl chloride was also an oxidant in the process. Mechanistic studies indicated that six-membered ruthenacycles were the key intermediate in the reaction.
The development of
mild and practical methods for the γ-arylation
of carbonyl compounds is an ongoing challenge in organic synthesis.
The first formal γ-arylation of carbonyl compounds via radical
relay cross-coupling of α-bromocarbonyl precursors with boronic
acids in the presence of alkenes is reported. This directing-group-free
protocol allows for the rapid and straightforward access to a wide
range of γ-arylated esters, ketones, and amides under ambient
conditions with excellent functional group tolerance.
The first example of the synthesis of m-alkylphenols via a ruthenium-catalyzed C-H bond functionalization of phenol derivatives with sec/tert-alkyl bromides is reported. Mechanistic studies indicated that the m-C-H bond alkylation may involve a radical process and that a six-membered ruthenacycle complex was the active catalyst. Moreover, this approach can provide an expedited strategy for the atom-/step-economical synthesis of many noteworthy pharmaceuticals and other functional molecules.
A ruthenium‐catalyzed meta‐selective CAr–H bond difluoroalkylation of 2‐phenoxypyridine using 2‐bromo‐2,2‐difluoroacetate has been developed. Mechanistic studies indicated that this difluoroalkylation might involve a radical process. Furthermore, a new method is reported for the synthesis of 2‐(meta‐difluoroalkylphenoxy)pyridine derivatives, which are present in many pharmaceuticals and other functional compounds.
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