A Practical and Efficient Synthesis of Enantiomerically Pure Di-tert-butyl-ethanediamine

All articles of this category A diastereoselective synthesis of 1,2-diamino-1,2-di- tert -butylethane has been developed by addition of tert -butyl magnesium chloride to a chiral bis-imine derived from glyoxal and ( S )-methylbenzylamine. Addition of the bis-imine to the Grignard reagent in hexane at 50 °C gave only one diastereomer detectable by 1 H and 13 C NMR. Hydrogenolysis of the phenylethyl groups led to the expected free diamine 3 in good yields. The absolute configuration ( R , R ) of the carbons bearing the tert -butyl groups has been confirmed by X-ray spectroscopy. chiral 1,2-diimine - diastereoselective addition - Grignard reagent - hydrogenolysis - ligand precursor