99646-06-7Relevant articles and documents
SYNTHESIS OF 1,3-DIOL DERIVATIVES FROM STERICALLY OVERCROWDED OXIRANES. RING-OPENING REACTIONS OF 1-t-BUTYL-1,2-EPOXYCYCLOHEXANE.
Corona, Tiberio,Crotti, Paolo,Ferretti, Maria,Macchia, Franco
, p. 1607 - 1616 (2007/10/02)
The acid-catalysed ring-opening reactions of 1-t-butyl-1,2-epoxycyclohexane (1) (methanolysis, hydrolysis, and trichloroacetolysis in non-protic solvents) lead to very complex mixtures.In these reactions, in addition to the non-addition products in which the t-butyl skeleton is still present, considerable amounts of other products are formed.These compounds include 1,3-secondary addition products and other rearranged non-addition products which arise by rearrangement of the original skeleton of (1), by methyl group migration; the aldehyde (20) which is lackig both the t-butyl group and the cyclohexane skeleton is also obtained.However the opening reactions of (1) in acid media are highly regioselective, most of the reaction products arising from C-O breaking on the tertiary carbon.The structures and the configurations of all the reaction products have been well established by a study of their i.r. and n.m.r. data; however, in some cases the structures and configurations were confirmed either through unequivocal syntheses and/or chemical correlations.The stereoselectivity of the trichloroacetolysis reactions of (1) is not completely anti, even if the amounts of 1,2 adducts formed are somewhat small, and the syn/anti ratio increases with the polarity of the solvent.The results obtained were rationalized through a mechanism analogous to that previously proposed for 2-aryl- and 2-ethynyl-oxiranes in which different kinds of carbenium ion species are involved.
