An efficient method for the preparation of N,N-disubstituted 1,2-diamines

C2-Symmetric 1,2-diamines are useful precursors to numerous reagents used in asymmetric synthesis and catalysis. We report here an efficient protocol for converting the two most commonly used trans-1,2-diamines to N,N-disubstituted derivatives, a transformation that simplifies the preparation of non-C2-symmetric diamines. Central to the method is the high-yielding conversion of the diamines to the corresponding monoacetylated derivatives via imidazoline intermediates.