Manganese palladium-catalyzed coupling

In a new and significant development, it was found that chlorocyclohexadienyl manganese tricarbonyl complexes undergo palladium-catalyzed coupling reactions with a variety of carbon nucleophiles to afford products from which hydride may be abstracted with trityl cation, thus generating new [( -arene)Mn(CO)3]+ complexes containing substituents that cannot be introduced in any other manner. This is particularly true of electron-withdrawing substituents. Scheme 16 illustrates the chemistry involved. 

Palladium(0)-catalyzed coupling of iodobenzene (153) and the commercial arylamine 154 afforded quantitatively the diarylamine 156 (Scheme 34) [178]. The oxidative cyclization of the diarylamine 156 to clausine L (148) is catalytic in palladium(II) and copper(II) acetate (or manganese(lll) acetate, respectively). Thus, air is the actual oxidizing agent in this process. For example, employing only... 

Palladium-Catalyzed Cross-Coupling Reactions of Benzylic Manganese Reagents... 

Table 8.17 Palladium-catalyzed cross-coupling reactions of benzyl manganese halides and phosphate with aryl iodides.

Sequential cross-coupling reactions of 2,4-dichloropurine 69 have been conducted. 2,6-Disubstituted purine 69 was cross-coupled with MeZnBr to give monosubstituted purine 70, which underwent Suzuki cross-coupling with phenylboronic acid to furnish disubstituted purine 71. Recently, the synthesis of 6-(2-hydroxyethyl)purines was developed based on the Negishi palladium-catalyzed cross-coupling reactions of 6-chloropurines with the Reformatsky reagent followed by reduction by sodium borohydride and treatment with manganese(IV) oxide. ... 

The metal-catalyzed cross-coupling of aryl-, heteroaryl-, and alkenyhnagnesium derivatives is a broad-scope transformation that has found many synthetic applications C(sp )-C(sp ) couplings are by far the most common. Catalysts by nickel, palladium, and iron complexes is most widespread, but the emerging fields of cobalt and manganese catalysis can also provide useful alternatives. 

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