1 0 0 0 OA 環拡大反応

著者
桧山 為次郎 野崎 一
出版者
The Society of Synthetic Organic Chemistry, Japan
雑誌
有機合成化学協会誌 (ISSN:00379980)
巻号頁・発行日
vol.35, no.12, pp.979-991, 1977-12-01 (Released:2009-11-13)
参考文献数
75
被引用文献数
10 11

Syntheses of hardly available ring structures through ring enlargement reactions are illustrated with the emphasis on the methods of high utility from the synthetic point of view.I One-Carbon Ring Enlargement. The molecular rearrangements involve active species such as carbonyl-diazomethane adducts, β-hydroxycarbenium ions, β-oxidocarbenoids, and β-bromo alkoxides respectively. Oxidative rearrangement is performed by means of cyanogen azide or thallium (III) nitrate. Bicyclo [n. 1.0] alkanes also are key intermediates for the one-carbon homologation. Photolysis of bicyclo [n. 2.1] alkanones having a carbonyl bridge undergoes Norrish Type I reaction resulting in ring expansion.II Two-Carbon Ring Enlargement. This methodology consists in the reaction of enamines of cyclic ketones with ketenes or acetylenes, acyloin condensation of cycloalkane-1, 2-dicarboxylic acid esters followed by thermolysis, and [1, 3] sigmatropic rearrangement.III Three-Carbon Ring Enlargement. Photolysis of α-cyclopropyl ketones and β, γ-unsaturated ketones, and fragmentation of bicyclo [n. 3.0] alkenones are discussed.IV Four-Carbon Ring Enlargement. Typical examples are the oxy-Cope rearrangement and fragmentation of bicyclo [n. 4.0] alkanes.V Miscellanea