A Convenient Generation of 2,3-Naphthalyne. Linear Annulation of Naphthalene and a New Naphthacene Synthesis

Article abstract of DOI:10.1021/jo00162a013

2,3-Naphthalyne (3) is conveniently generated by treating 2,3-dibromonaphthalene (9) with phenyllithium and is used in a two-step sequence to prepare naphthacene (1) and 1,2,3,4-tetrafluoronaphthacene (17).Thus, the cycloadditions of 3 with 2-methylisoindole (13) and 2-methyl-4,5,6,7-tetrafluoroisoindole (14) afford the naphthacenimines 15 and 16, respectively.Deamination with m-chloroperbenzoic acid (for 15) and dichlorocarbene (for 16) affords 1 and 17 in 44percent and 63percent overall yield from 9, respectively.Similarly, cycloadditions of 3 with furan and N-tert-butylpyrrole give anthracene, after extrusion of the heteroatom bridge.