Download PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... Heating pyranulose 4 and cinnamate 2 in the presence of 2,6-di-t-butylpyridine in CH 3 CN afforded the [5+2] cycloadduct, which was hydrolyzed to give 13% of cartorimine (1). ... Heating the pyranulose diacetate and the cinnamate ester in the presence of 2,6-di-t-butylpyridine in CH 3 CN ...