Hexatriene formation from the regiospecific alkene cross-metathesis of trans-1-(buta-1,3-dien-1-yl)-2-acryloyloxynaphthalene

Wittig olefination of 2-hydroxy-1-naphthaldehyde with allylidenetriphenylphosphorane afforded trans-1-(buta-1,3- dien-1-yl)-2-naphthol in good yield. Subsequent O-acylation with acryloyl chloride provided the corresponding acrylate ester. Attempts to effect cyclisation of the latter by ring-closing metathesis with Grubbs' 2nd generation catalyst failed to provide 5H-naphth[2,1-b]oxocin-5-one and instead induced a novel cross-metathesis reaction to generate trans,trans,trans-1,6-bis(2-acryloyloxynaphthalen-1-yl) hexa-1,3,5-triene, the structure of which was established by ¹H NMR spectroscopy and by X-ray crystallography.