An Efficient Transformation of Cyclic Ene-carbamates into ω-(N-Formylamino)carboxylic Acids by Ruthenium Tetroxide Oxidation

The ruthenium tetroxide (RuO4) oxidation of cyclic ene-carbamates resulted in the endo-cyclic carbon–carbon double bond cleavage to afford the corresponding ω-(N-formylamino)carboxylic acids in good yields. Substituted cyclic ene-carbamates derived from (3R)-3-hydroxypiperidine hydrochloride were converted into the N-Boc 4-aminobutyric acids by utilization of the RuO4 oxidation as the key step, which were further transformed into (3R)-4-amino-3-hydroxybutyric acid, an important key intermediate for the synthesis of L-carnitine.