Palladium-catalyzed Aminomethylation Of 1,3-Dienes With Aminals

Transition-metal catalyzed reactions of constructing C-N bond and C-C bond through nitrogen-containing synthetic blocks are two kinds of important and effective ways to prepare organic nitrogenous molecules.Amines are a kind of crucial materials and exist widely in the nature.Meanwhile,?,?-unsaturated allyl amine and its derivatives are key building blocks for the synthesis of various nitrogenous compounds,which exist extensively in physiologically active substances and synthetic chemistry.In consequence,the investigation of the ways to synthesize this type of materials effectively and systematically is very necessary.To date,there are few reports on the methods available for constructing ?,?-unsaturated allyl amines(pentadienyl amines)scaffold.Herein,we present an efficient palladium-based catalyst system for the selective aminomethylation of conjugated 1,3-dienes with aminals to syhthesize ?,?-unsaturated allyl amines efficiently.The results are as follows:A new palladium-catalyzed selective aminomethylation of conjugated 1,3-dienes with aminals through carbon-carbon bond forming process is developed.The reaction proceeds through a cyclometalated Pd(II)complex as key reactive intermediate generated by C-N activation of aminals.This process provides an effective and systematical approach for the synthesis of linear ?,?-unsaturated allyl amine with perfect regioselectivity and high ratio of cis-and trans-isomers.Most of the substrates examined in this reaction provided the corresponding products in good to excellent yields,which was up to 95%.In addition,the reaction proceeded smoothly on a gram scale even at a lower catalyst loading and amount of solvent,affording the product in 81% yield.