Arenes oxidative cross-couplings

Dohi T, Ito M, Morimoto K, Wata M, Kita Y (2008) Oxidative cross-coupling of arenes induced by single-electron transfer leading to biaryls by use of organoiodine(III) oxidants. Angew Chem Int Ed 47 1301-1304... 

Although not directly relevant to this review, it should be noted that Sanford, Shi and Buchwald have also reported a palladium-catalyzed reaction for the chemo-and regioselective oxidative cross-coupling between ligand coordinated L-Cat-H substrates and simple arenes (Ar-H) [55-57]. 

Scheme 15 Pd-catalyzed oxidative cross-coupling between simple arenes...

Soonafterward, Buchwald and coworkers reported an efficient Pd-catalyzed oxidative cross-coupling of A-acetanilides with simple arenes in a similar manner [70]. In the presence of 5-10 mol% Pd(OAc)2 and 10-20 mol% DMSO, the cross-coupling reaction took place smoothly between anilides and 4—11 equiv. of simple arenes in TFA under an oxygen atmosphere (Scheme 23). The reaction conditions could tolerate a wide range of substrates. The metal-free oxidant represents a great advantage of the current catalytic system. 

Pd-catalyzed oxidative cross-coupling of arenes with chromanones was reported by the Hong group [36]. These reactions proceed through in situ formation of the chromones via Pd-catalyzed dehydrogenation of the starting chromanones (Scheme 24.40, step i). Subsequent coupling of the aUcene moiety in the chromones with the arenes affords the final products. 

Afterwards, Antonchick and coworkers [105] successfully extended this methodology to the oxidative cross coupling of heteroarenes and simple unfunctionalized alkanes (Scheme 40 (1)). The new C(sp )-C(sp ) bond formation occurred selectively at the electron-deficient site of the arene. The reaction was... 

The Discovery and Development of a Palladium(II)-CataIyzed Oxidative Cross-Coupling of Two Unactivated Arenes... 

Table 4 Scope of the C3 and C2 oxidative cross-coupling of indole with simple arenes... 

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