Enantioselective 1,3-Dipolar Cycloaddition Reactions of C-Carboxy Ketonitrones and Enals with MacMillan Catalysts: Evidence of a Nonconcerted Mechanism. - Ben Ayed, Kawther; Laurent, Mathieu Y.; Martel, Arnaud; Selim, Khalid B.; Abid, Souhir; Dujardin, Gilles (European Journal of Organic Chemistry, 2017)