Synthesis of pyranonaphthoquinone antibiotics involving the ring closing metathesis of a vinyl ether

The synthesis of two antibiotic pyranonaphthoquinones was performed by a straightforward synthetic route utilizing ring closing metathesis. Vinylation of 3-(1-propenyl)-2-hydroxymethyl-1.4-dimethoxynapthalene under iridium catalysis and subsequent ring closing metathesis of 3-(1-propenyl)-2-vinyloxymethyl-1.4-dimethoxynaphthalene with Grubbs' catalyst paved the way to the natural antibiotics pentalongin and psychorubrin. (C) 2004 Elsevier Ltd. All rights reserved.