Bonar-Law, R. P., Davies, A. P., Dorgan, B. J., Reetz, M. T., & Wehrsig, A. (1990). The “benzostabase” protecting group for primary amines; application to aliphatic amines. Tetrahedron Letters, 31(46), 6725-6728. doi:10.1016/S0040-4039(00)97158-2.