Development of an Enyne Metathesis/lsomerization/Diels-Alder One-Pot Reaction for the Synthesis of a Novel Near-Infrared (NIR) Dye Core

摘要

N-Alkyl-N-allyI-2-alkynylaniline derivatives undergo a tandem ring closing enyne metathesis/isomerization/DielsAlder cycloaddition sequence in the presence of a secondgeneration Grubbs catalyst and dienophiles. In practice, the acyclic enyne in the presence of the ruthenium alkylidene first undergoes ring closing metathesis to generate cyclic 4vinyl-1,2-dihydroquinolines; following diene isomerization and then the addition of a dienophile, these ring-closing metathesis products are selectively converted into a 7methyl-4H-naphtho[3,2,1-de]quinoline-8,11-dione core. Overall,the reaction sequence converts simple aniline derivatives into a-conjugated small molecules, which have characteristic absorption in the near infrared region, in a single operation through three unique ruthenium-catalyzed transformations.