Iridium-Catalyzed Addition of Water and Alcohols to Terminal Alkynes

Iridium-Catalyzed Addition of Water and Alcohols to Terminal Alkynes 

The addition of water and alcohols to nonactivated terminal alkynes was promoted by [Ir(cod)2] BF4 combined with Lewis acids and phosphate [55]. Thus, terminal alkynes such as 1-octyne 122 reacted with butanol 123 to afford 2-octanone dibu-tylketal 124 (Equation 10.31). 

The iridium-catalyzed addition of water could be applied to the reaction of a,03-diynes. Thus, 1,7-octadiyne 125 was converted to l-(2-methylcyclopent-l-enyl)ethanone 127 (Equation 10.32). The formation of 127 was explained by assuming intramolecular aldol condensation of the resulting 2,7-octadione by Lewis acid. 

Iridium-Catalyzed Direct Arylation of Aromatic C—H Bonds 

Arylation of benzene 128 with aryl iodides 129 via direct C—H bond activation was achieved in the presence of [Cp lrHCl]2 and KO Bu to afford corresponding biaryl 130 (Equation 10.33) [56]. The phenyl radical would participate as an intermediate in this reaction. 

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