Synthesis of Functionalized Cyclopentanes, Cyclohexanes and Cycloheptanes by a Silicon‐Induced Domino Reaction

Abstract

Abstract 1,3‐Functionalized cyclopentanes, ‐hexanes and ‐heptanes are obtained by addition of lithiated silyldithioacetals 7 to epoxyhomoallyl tosylates 4–6 , The reaction involves a cascade of epoxide ring opening, of Brook 1,4‐rearrangement and tosylate substitution. The method is particularly suitable for the preparation of cyclopentanes, whereas cyclohexanes and ‐heptanes are formed in yields only up to 49%. Use of enantiomerically pure epoxides provides optically active cyclopentanes ( S )‐ 10b, d, 11a as well as oxetanes ( S )‐ 14a, b. Hydrolysis of the dithioacetal function leads to the corresponding ketones 12 , Cyclization of epoxide 24b gives an anellated cyclopentane 26 , the configuration of which was established by X‐ray structural analysis of dinitrobenzoate 27 . Use of epoxide 29b provides the anellated tetrahydrofuran 30 .