One-Shot Double Amination of Sondheimer–Wong Diynes: Synthesis of Photoluminescent Dinaphthopentalenes

Photoluminescent
diamino-substituted dinaphtho­pentalenes
were synthesized successfully by the treatment of in situ prepared dinaphtho­cyclo­octadiyne with lithium amide.
This reaction involves a series of transformations including the nucleophilic
addition of the lithium amide to a triple bond of the cyclooctadiyne
moiety, transannulation, protonation of the resulting pentalene anion,
and the nucleophilic substitution of the pentalene core with the lithium
amide. In this procedure, a novel double amination step plays a key
role. When the diamino-substituted dinaphtho­pentalenes were
irradiated with UV light in toluene, fluorescence was observed at
around 580 nm (ΦF < 0.03).