Remarkably stable iron porphyrins bearing nonheteroatom-stabilized carbene or (alkoxycarbonyl)carbenes: isolation, X-ray crystal structures, and carbon atom transfer reactions with hydrocarbons.
Reactions of [Fe(TPFPP)] (TPFPP = meso-tetrakis(pentafluorophenyl)porphyrinato dianion) with diazo compounds N(2)C(Ph)R (R = Ph, CO(2)Et, CO(2)CH(2)CH=CH(2)) afforded [Fe(TPFPP)(C(Ph)R)] (R = Ph (1), CO(2)Et (2), CO(2)CH(2)CH=CH(2) (3)) in 65-70% yields. Treatment of 1 with N-methylimidazole (MeIm) gave the adduct [Fe(TPFPP)(CPh(2))(MeIm)] (4) in 65% yield. These new iron porphyrin carbene complexes were characterized by NMR and UV-vis spectroscopy, mass spectrometry, and elemental analyses. X-ray crystal structure determinations of 1.0.5C(6)H(6).0.5CH(2)Cl(2) and 4 reveal Fe=CPh(2) bond lengths of 1.767(3) (1) and 1.827(5) A (4), together with large ruffling distortions of the TPFPP macrocycle. Complexes 2 and 4 are reactive toward styrene, affording the corresponding cyclopropanes in 82 and 53% yields, respectively. Complex 1 is an active catalyst for both intermolecular cyclopropanation of styrenes with ethyl diazoacetate and intramolecular cyclopropanation of allylic diazoacetates. Reactions of 2 and 4 with cyclohexene or cumene produced allylic or benzylic C-H insertion products in up to 83% yield.
Li
Yan
Y
Department of Chemistry and Open Laboratory of Chemical Biology of the Institute of Molecular Technology for Drug Discovery and Synthesis, The University of Hong Kong, Pokfulam Road, Hong Kong.
Huang
Jie-Sheng
JS
Zhou
Zhong-Yuan
ZY
Che
Chi-Ming
CM
You
Xiao-Zeng
XZ
D002244:Carbon / Q000737:chemistry; D018360:Crystallography, X-Ray; D005290:Ferric Compounds / Q000737:chemistry; D006838:Hydrocarbons / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D008665:Metalloporphyrins / Q000737:chemistry; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry* / Q000302:isolation & purification; D008958:Models, Molecular; D015394:Molecular Structure; D011166:Porphyrins / Q000737:chemistry* / Q000302:isolation & purification; D005464:Fluorobenzenes; D005466:Fluorocarbons
D002244:Carbon; D005290:Ferric Compounds; D006838:Hydrocarbons; D007501:Iron; D008665:Metalloporphyrins; D008697:Methane; D011166:Porphyrins; C093411:tetrakis(pentafluorophenyl)porphyrinato iron(III) chloride; D005464:Fluorobenzenes; D005466:Fluorocarbons; C030011:carbene