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The synthesis of two new chiral guanidines 5 and 12 and derived guanidinium salts 6, 11, 13 -15 with one and three N-(1-phenylethyl) substituents is described. In both cases, the well-precedented, reliable route via chloro-formamidines was taken. Since direct attachment of the N-methyl-N-(1-phenethyl)-amino group failed, the two-step protocol -introduction of the primary 1-phenethylamino group first followed by N-methylation -was employed. Crystal structures and NMR data reveal, that the sterically highly congested "tris" salt -with formal C 3 symmetry, albeit unsymmetrical in the crystal -constitutes an intriguing structure with two rotamers present in solution.

C12H14Br2N2O5, orthorhombic, P212121 (no. 19), a = 5.7982(4) Å, b = 8.5837(6) Å, c = 29.676(2) Å, V = 1477.0 Å3, Z = 4, Rgt(F) = 0.0558, wRref(F2) = 0.1248, T = 100 K.

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