Sterically Congested Polycyclic Hydrocarbons with Nonoptimal Geometries. 4,5-Didehydroacenaphthene as a Precursor for the Synthesis of 7,14-Diphenyl-8,9-(1',8'-naphthenylene)acephenanthrene

Article abstract of DOI:10.1021/jo00010a010

A multistep synthetic route for the synthesis of the reactive intermediate 4,5-didehydroacenaphthene (15) is described.A mixture of N-1-, N-2-, and N-3-aminoacenaphtho<4,5-e>triazoles is produced, which is oxidized by lead tetraacetate (LTA) to the corresponding aryne.The N-2-triazole is oxidized by LTA to 7-cyano-1-(cyanomethylene)indan (18), whose structure was verified by X-ray analysis.Intermediate 15 was trapped by 7,9-diphenyl-8H-cyclopentaacenaphthylen-8-one (acecyclone) to produce the congested hydrocarbon 7,14-diphenyl-8,9-(1',8'-naphthenylene)acephenanthrene (20).There is a small deviation from planarity for 20, and this is modeled by MMX calculations and verified by X-ray crystallographic analysis of the structure.