N Boc aromatic imines

Aminals, compounds having two amino groups bound to the same carbon atom, are represented in many medicinal agents having versatile therapeutic action, such as proteinase inhibitors and neurotensins. Antilla and coworkers developed an en antioselective synthesis of protected aminals from the amidation reaction of N Boc imines with a series of sulfonamides catalyzed by chiral phosphoric acids (Scheme 3.54a) [111]. In this novel enantioselective transformation, phosphoric acid 9 exhibited excellent catalytic activity and enantioselectivity in addition to N Boc aromatic imines. The enantioenriched aminal products were stable upon storage neither decomposition nor racemization was observed in solution over several days. The same research group reported the enantioselective amidation reaction of N Boc aromatic imines with phthalimide or its derivatives (Scheme 3.54b) [112]. 

In 2009, the Jorgensen group developed the organocatalytic asymmetric addition of P-keto-benzothiazole-sulfones to N-Boc aromatic imines based on the thiourea organocatalyst 61 and using as solvent, unusually, propionitrile (Scheme 29.33) [70]. The reaction proceeds with moderate yields, and stereoselectivities from moderate to excellent The initially formed adducts 62 were easily transformed into different types of protected amines like the aUyHc amines 63, or P-amino ketones 64 and 65. 

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