Propargyl aza-Claisenrearrangement of 4-propargylaminoisoxazoles 1 proceeded in the presence of cationic gold(I) catalysts to give 4-amino-5-allenylisoxazoles 2 in good to high yields. The silyl group at the terminal alkyne and a cationic gold(I) catalyst bearing a sterically bulky ligand are essential for the generation of isolable allene intermediates. The N-protection of the generated 4-amino-5-allenylisoxazoles