An efficient transformation of cyclic ene-carbamates into omega-(N-formylamino)carboxylic acids by ruthenium tetroxide oxidation.

The ruthenium tetroxide (RuO(4)) oxidation of cyclic ene-carbamates resulted in the endo-cyclic carbon-carbon double bond cleavage to afford the corresponding omega-(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 RuO(4) 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.