Development of an Enyne Metathesis/Isomerization/Diels–Alder One‐Pot Reaction for the Synthesis of a Novel Near‐Infrared (NIR) Dye Core |
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Authors: | Kohei Yamashita Yuki Fujii Shohei Yoshioka Dr Hiroshi Aoyama Dr Hirofumi Tsujino Prof?Dr Tadayuki Uno Prof?Dr Hiromichi Fujioka Dr Mitsuhiro Arisawa |
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Institution: | Graduate School of Pharmaceutical Sciences, Osaka University, 1‐6 Yamada‐oka, Suita, Osaka 565‐0871 (Japan) |
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Abstract: | N‐Alkyl‐N‐allyl‐2‐alkynylaniline derivatives undergo a tandem ring‐closing enyne metathesis/isomerization/Diels–Alder cycloaddition sequence in the presence of a second‐generation Grubbs catalyst and dienophiles. In practice, the acyclic enyne in the presence of the ruthenium alkylidene first undergoes ring‐closing metathesis to generate cyclic 4‐vinyl‐1,2‐dihydroquinolines; following diene isomerization and then the addition of a dienophile, these ring‐closing metathesis products are selectively converted into a 7‐methyl‐4H‐naphtho3,2,1‐de]quinoline‐8,11‐dione core. Overall, the reaction sequence converts simple aniline derivatives into π‐conjugated small molecules, which have characteristic absorption in the near‐infrared region, in a single operation through three unique ruthenium‐catalyzed transformations. |
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Keywords: | cycloaddition domino reactions dyes/pigments heterocycles metathesis |
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