Oxidative C–H functionalization: a novel strategy for the acetoxylation/alkoxylation of arenes tethered to 3,4-dihydroisoquinolines

Hydrolysis of dihydroisoquinoline derivatives activated by sulfonyl or acyl chloride

A new, efficient, and mild strategy for hydrolysis of 3,4-dihydroisoquinoline imines activated by sulfonyl chloride or acyl chloride has been developed, by which method ketosulfonamides and ketoamides have been synthesized. This process tolerates broad scope with respect to both the sulfonyl chloride and acyl chloride with moderate to excellent yields. This protocol features a broad substrate scope for various kinds of 3,4-dihydroisoquinoline and mild reaction conditions without using strong acidic or basic conditions. These features show that this user-friendly and simple system could be applied in the future to the synthesis of a broader range of amino benzophenones.

Hypervalent iodine promoted ortho diversification: 2-aryl benzimidazole, quinazoline and imidazopyridine as directing templates

The mild and efficient palladium-catalyzed ortho C(sp²)-H diversification of (NH)-free 2-substituted benzimidazole, quinazoline, and imidazopyridine is reported using hypervalent iodine as the key reagent. Acetoxy, aryl, iodide and nitro functional groups were introduced on the same substrate by simply shifting the reaction conditions in the presence of inorganic additives (Cs₂CO₃, I₂, NaNO₂) and the hypervalent iodine reagent (diacetoxyiodo)benzene (PIDA) under aerobic conditions. The combination of NaNO₂ with PIDA was successfully employed in Pd-catalyzed C-H bond nitration to achieve a library of nitrated 1,3 N-heterocycles. This versatile ortho C(sp²)-H activation strategy features operational simplicity, short reaction times, and ample substrate possibilities, it requires no ligands or silver salts as additives, and it shows good tolerance of oxidation prone functional groups.

Pd(OAc)2-catalysed regioselective alkoxylation of aryl (β-carbolin-1-yl)methanones via β-carboline directed ortho-C(sp(2))-H activation of an aryl ring

Synthesis of (2-alkoxyphenyl)(9H-pyrido[3,4-b]indol-1-yl)methanone via Pd(OAc)2-catalyzed regioselective alkoxylation of aryl (β-carbolin-1-yl) methanones employing β-carboline directed ortho-C(sp(2))-H activation of an aryl ring under oxidative conditions is described.

Selective N-chelation-directed C-H activation reactions catalyzed by Pd(II) nanoparticles supported on multiwalled carbon nanotubes

N-Chelation-directed C-H activation reactions that utilize the Pd(II)/Pd(IV) catalytic cycle have been previously reported. To date, these reactions employ only homogeneous palladium catalysts. The first use of a solid-supported Pd(II) catalyst [Pd(II) nanoparticles on multiwalled carbon nanotubes, Pd(II)/MWCNT] to carry out N-chelation-directed C-H to C-O, C-Cl, and C-Br transformations is reported. The results presented demonstrate that the solid-supported Pd(II)/MWCNT catalyst can effectively catalyze C-H activation reactions using the Pd(II)/Pd(IV) catalytic cycle.

Microwave-assisted, ruthenium-catalyzed intramolecular amide-alkyne annulation for the rapid synthesis of fused tricyclic isoquinolinones

Microwave accelerated synthesis of tricyclic isoquinolinones has been accomplished through a domino C–C and C–N bond formation by an intramolecular C–H activation.