2008 年 66 巻 2 号 p. 158-171
The acid mediated carbon-carbon bond formation promoted by elimination of small molecule of carbon monoxide or hydrogen and the related reactions are discussed. The specific decarbonyla-tive arylation reactions of a-alkoxy- or a-oxocarboxylic acids with the aid of acidic mediator such as P2O5-MSOH or TFOH affording various arylated products are presented. Furthermore, the acid mediated dehydrogenafive formation of enol ethers or equivalents followed by crossed-aldol addition to activated benzaldehyde derivative or equivalents giving a, β-unsaturated carbonyl compounds or 1-alkoxy-2-alkylindenes is discussed. The elucidation of the structural requirements, the reaction routes, and the reaction mechanisms for these molecular transformations are described in detail. Some related reaction behaviors such as distinction in regiospecificity and dependence on acidic mediator of acid-mediated aroylation of γ- or δ-oxocarboxylic acids and intramolecular electrophilic aromatic substitution of a-alkylcinnamaldehydes affording 1-alkoxy-2-alkylindenes are also discussed.