Lewis acids in the synthesis of naphthoquinonylbenzo[g]chromenediones, derivatives of mesocentroquinone, a metabolite of the sea urchins Mesocentrotus nudus and Strongylocentrotus intermedius
摘要
An approach was developed for the synthesis of naphthoquinonylbenzo[g]chromenedions, derivatives of mesocentroquinone, a metabolite of the sea urchins Mesocentrotus nudus and Strongylocentrotus intermedius. The key stage in the developed approach is the previously undescribed heterodiene condensation of 2-oxo-3-alkylidene- and 3-alkenyl-2-hydroxy-1,4-naphthoquinones formed during dehydrobromination of the corresponding 3-(1-bromoalkyl)-2-hydroxy derivatives in the presence of Lewis acid (SnCl4).