Combining a suspension of 5 in DCM with a slight excess of diethylamine yields 7 in less than five minutes (Figure ). A simple workup provides the diethylammonium salt of 7, and we were able to obtain a crystal structure of this compound (Figure ). We were also able to prepare 7 by treatment of a mixture of 3 and 4 with diethylamine, although in a lower isolated yield (see SI).