Details

Autor(en) / Beteiligte

• Morimoto, Yuki
• Osuka, Atsuhiro
• Tanaka, Takayuki

Titel

Synthesis, properties and reactivity of an ortho-phenylene-cyclopentene-bridged tetrapyrrole

Ist Teil von

• Journal of porphyrins and phthalocyanines, 2021-10, Vol.25 (10n12), p.937-943

Ort / Verlag

Singapore: World Scientific Publishing Company

Erscheinungsjahr

2021

Beschreibungen/Notizen

• Increasing the number of meso-methine carbons of porphyrin has led to a creation of a series of vinylogous expanded porphyrins, while the introduction of an ortho-phenylene-unit as a pyrrole-connecting two-carbon bridge usually leads to prevention of effective macrocyclic conjugation. Cyclopentene can serve as a conjugative bridge to increase the macrocyclic conjugation owing to its cis-geometry. In this work, ortho-phenylene-cyclopentene-bridged tetrapyrrole 5 was prepared on the basis of a coupling strategy. The tetrapyrrole 5 exhibited slightly more conjugative features as compared to ortho-phenylene-bridged tetrapyrrole 4. Oxidation of 5 with [bis(trifluoroacetoxy)iodo]benzene (PIFA) at low temperature afforded a partly fused tetrapyrrolic compound 9 having a spiro-connected pyrrolo[2,1- a ]isoindole moiety. Ortho-phenylene-cyclopentene-bridged cyclic tetrapyrrole has been synthesized by Suzuki-Miyaura coupling of diborylated dipyrrole with 1,2-dibromo-1-cyclopentene. The new porphyrin(2.2.2.2) analog displayed a twisted structure in the solid state. Mild oxidation with PIFA at low temperature afforded an unexpected N–C linked product.