New, short synthesis of arylnaphthofuranone lignans based on reactions of o-aroylbenzyllithiums with furan-2(5H)-one

Abstract

A simple and general method to prepare 9-arylnaphtho[2,3-c]furan-1(3H)-one derivatives has been developed. The reaction of o-aroylbenzyllithiums with furan-2(5H)-one gave the corresponding adducts 5–8 and 5′–7′, which upon treatment with thionyl chloride in pyridine followed by dehydrogenation with Pd–C in refluxing p-cymene afforded the arylnaphthofuranone derivatives 13–16. The process proved to be applicable to the preparation of some 1-aryl type naphthofuranone lignans (collinusin, dehydrodimethylretrodendrin and justicidin B).