16121-01-0Relevant articles and documents
ENAMINE CHEMISTRY-XVIII. THE FORMATION OF HEXAHYDROCHROMANE-8a-AMINES BY REDUCTIVE CYCLISATION OF ENAMINES
Carlsson, S.,Lawesson, S.-O.
, p. 3585 - 3590 (2007/10/02)
Enamines (1) derived from cyclohexanone or cyclopentanone are reacted with electrophilic olefins (ethyl acrylate, ethyl 2-methylacrylate, ethyl 2-butenoate) to give the new enamines, 2.When 2 is reacted with LiAlH4, reductive cyclisation takes place giving hexahydrochromane-8a-amines of octahydrocyclopentapyrane-7a-amines, 3, in quantitative yields, 3 is hydrolyzed with dilute aqueous hydrochloric acid to hexahydrochromane-8a-ols of octahydrocyclopentapyrane-7a-ols (4) and reacts also with oxalic acid in refluxing dioxane to form the condensed dihydropyranes, 5.