- 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