139745-70-3Relevant academic research and scientific papers
Steric and Electronic Effects on the Photochemical Reactivity of Oxime Acetates of β,γ-Unsaturated Aldehydes
Armesto, Diego,Horspool, William M.,Gallego, Mar G.,Agarrabeitia, Antonia R.
, p. 163 - 170 (2007/10/02)
A general synthesis of 5-unsubstituted N-acetoxy 3,3-dimethyl-1-azapenta-1,4-dienes starting from 2-(1,3-dithian-2-yl)-2-methylpropanal is described.The influence of 5-phenyl, 4-phenyl, 5-cyclohexyl, 5-tert-butoxycarbonyl and 5,5-dicyclohexyl substitution on the outcome of the photochemical reactions of the oxime acetates of β,γ-unsaturated aldehydes has been studied with a view to proving or disproving the operation of a deactivating free rotor in the aza-di-?-methane rearrangement.The results obtained show that if the radical formed at C-5 can be stabilized by conjugation with an aryl group or by certain types of disubstitution then the aza-di-?-methane rearrangement takes place successfully.In any other situation the reaction fails.These results clearly show that the free rotor effect is not responsible for the failure of C-5 monosubstituted 1-aza-1,4-dienes to undergo the aza-di-?-methane rearrangement.
