Title:Some Terminally Alkenyl-substituted Porphyrins: Synthesis and Attempts of Heck Reaction Leading to Porphyrin–Azulene Dyads
Volume: 28
Issue: 19
Author(s): Stanisław Ostrowski*, Sebastian Grzyb and Bartosz Godlewski
Affiliation:
- Faculty of Chemistry, Warsaw University of Technology, ul. Noakowskiego 3, 00-664 Warszawa, Poland
Keywords:
Porphyrins, azulene derivatives, Heck reaction, vinyl derivatives, dyads, catalysts, palladium.
Abstract: The synthesis of meso-tetraphenylporphyrin derivatives, double functionalized in
one of the phenyl rings (with a nitro group and carbon substituents), is described. 5-(4-
Nitroaryl)-10,15,20-triarylporphyrinates react, in the presence of a base (t-BuOK), with carbanions
containing a leaving group at the carbanionic center to give products of substitution of
hydrogen at ortho-position to the nitro group via vicarious nucleophilic substitution scheme.
Their alkylation with allyl bromide or 4-bromobut-1-en (t-BuOK/DMF, at 0-5°C) leads to
porphyrins bearing side alkyl chain with a terminal double bond in yields of up to 82%. The
above-mentioned double-substituted intermediates are very convenient substrates for Heck
cross-coupling reaction. In this study, the synthesis of porphyrin–azulene dyads is reported. In
some cases, the formation of highly conjugated systems is observed, with moderate yield.
Their structures are interesting from both the porphyrin and azulene point of view.
