A NEW SYNTHETIC ROUTE TO 2-SUBSTITUTED NAPHTHO[2,3-B]FURAN-4,9-DIONE

4,9-Dimethoxynaphtho[2,3-b]furan 9 was obtained in 91% yield via the r eductive methylation of naphtho[2,3-b]furan-4,9-dione 2. After treatme nt of 9 with butyllithium, the mixture was allowed to react with N,N-d imethylacetamide, followed by oxidization with cerium(IV) diammonium n itrate to give 2-acetylnaphtho[2,3-b]furan-4,9-dione 1. 2-Formylnaphth o[2,3-b]furan-4,9-dione 13 and 2-trimethylsilylnaphtho[2,3-b]furan-4,9 -dione 14 were also obtained from 9 by a similar method. The halodesil ylations of 14 easily gave 2-iodonaphtho[2,3-b]furan-4,9-dione 16, 2-b romonaphtho[2,3-b]furan-4,9-dione 17, and 2-chloronaphtho[2,3-b]furan- 4,9-dione 18 in 82%, and 93% and 83% yield, respectively. Furthermore, the nitrodesilylation of 14 gave 2-nitronaphtho[2,3-b]furan-4,9-dione 3 in 77% yield.