Asymmetric aza-henry reaction under phase transfer catalysis: An experimental and theoretical study

作者：Gomez Bengoa Enrique; Linden Anthony; Lopez Rosa; Mugica Mendiola Idoia; Oiarbide Mike; Palomo Claudio^*

来源：Journal of the American Chemical Society, 2008, 130(25): 7955-7966.

DOI：10.1021/ja800253z

An efficient catalytic asymmetric aza-Henry reaction under phase transfer conditions is presented. The method is based on the reaction of the respective nitroalkane with a-amido sulfones effected by CsOH center dot H2O base in toluene as solvent and in the presence of cinchone-derived ammonium catalysts. This direct aza-Henry reaction presents as interesting features its validity for both nonenolizable and enolizable aldehyde-derived azomethines and the tolerance of nitroalkanes, other than nitromethane, for the production of beta-nitroamines. The synthetic value of the methodology described is demonstrated by providing (a) a direct route for the asymmetric synthesis of differently substituted 1,2-diamines and (b) a new asymmetric synthesis of gamma-amino alpha,beta-unsaturated esters through a catalytic, highly enantioselective formal addition of functionalized alkenyl groups to azomethines. Finally, a preferred TS that nicely fits the observed enantioselectivity has been identified. Most remarkable, an unusual hydrogen bond pattern for the catalyst-nitrocompound-imine complex is predicted, where the catalyst OH group interacts with the NO2 group of the nitrocompound.

• 出版日期2008-6-25