Angeli's salt undergoes a quantitative reaction with 1,3-diphenylisobenzofu
ran in a methanol/water solution at room temperature to give a product (1)
explicable by an initial [4+2] cycloaddition reaction. Under the same condi
tions, Angeli's salt reacts with 1-naphthaldehyde to give 1-naphthoic acid
in good yield. This reaction can also be explained by an initial [2+2] cycl
oaddition to give a hydroxamic acid, which is then hydrolyzed to the carbox
ylic acid. (C) 1999 Elsevier Science Ltd. All rights reserved.