Robust carbene ruthenium-porphyrin catalysts for cyclopropanation reaction of a wide variety of alkenes

Abstract

A series of carbene ruthenium-porphyrins [ Ru ( por )(: CR 1 R 2)] ( por = TPP ; R 1 = R 2 = p- C 6 H 4 Cl 2, p- C 6 H 4 Me 3, p- C 6 H 4 Ph 4; R 1 = Ph , R 2 = p- C 6 H 4 Ph 6; R 1 = Ph , R 2 = COPh 7; R 1 = p- C 6 H 4 Me , R 2 = CO (p- C 6 H 4 Me ) 8; R 1 = COMe, R 2 = COPh 9; por = TTP ; R 1 = R2 = Ph 1', COPh 5') were synthesized and characterized. The starting material [ Ru ( por )( CO )] was treated with corresponding diazo compounds N 2 CR 1 R 2 in CH 2 Cl 2 or octane for the diaryl carbene complexes 1', 2-4 and 6, while it was subjected to photolysis in THF , followed by reflux with the diazo compounds for the acyl carbene complexes 5' and 7-9. The compounds were robust in octane under reflux and were able to catalyze cyclopropanation reactions with methyl diazoacetate (MDA) toward a wide variety of alkenes. Monocyclopropanation of 25 alkenes was demonstrated with catalyst 3 in octane under reflux. By reaction with more than equimolar amounts of MDA in the presence of catalyst 9, the first porphyrin-catalyzed biscyclopropanation was attained toward nonconjugated α, ω-dienes, viz. 1,5-hexadiene and 1,7-octadiene.

(5,10,15,20-Tetraphenylporphyrinato-κ4 N)(2,2,2-trifluoro-1-phenylethylidene-κC 1)ruthenium(II): a stable fluorinated alkylidene complex of a ruthenium(II) porphyrin

“…1, the five-coordinate ruthenium atom is bound to the carbene carbon atom to which the phenyl and trifluoromethyl groups are attached, lying in a distorted square-pyramidal geometry in (I). There seems to be no remarkable difference in the bond lengths and angles about the carbene carbon atom, compared with those for the fivecoordinate ruthenium(II)-porphyrin analogs reported so far, in the ranges 1.82-1.87 Å and 111-118° (Li et al, 2004;Wada et al, 2008). The porphyrin core in (I) is deformed in domed conformation with maximum and minimum deviations from the C 20 N 4 least-squares plane of 0.205 (2) and -0.209 (2) Å for N1 and C17, respectively.…”

“…The trifluoromethyl group has so large van der Waals radius (2.7 Å) (Seebach, 1990) that the steric repulsion toward the porphyrin core would affect some structural features. The ruthenium atom is situated at 0.3301 (5) Å out of the C 20 N 4 least-squares plane toward the carbene moiety in (I), while the displacements are 0.216 (2)-0.287 (1) Å in other tetraphenyl-or tetra(ptolyl)porphyrin complexes (Wada et al, 2008). In addition, the Ru═C45 bond is slightly tilted from the normal to the C 20 N 4 least-squares plane, as indicated by the larger C45═Ru-N1 angle [97.70 (8)°] than the C45═Ru-N3 [93.42 (8)…”

“…For the preparation of the precursor of the 1-phenyl-2,2,2trifluoroethylidene ligand, see: Shepard & Wentworth (1967). For related structures, see: Che & Huang (2002); Li et al (2004); Wada et al (2008). For C-HÁ Á Á interactions, see: Hunter et al (2001).…”

Ruthenium-Porphyrin-Catalyzed Carbenoid Transfer Reactions

“…An application we developed for this type of reaction catalyzed by 2c is the synthesis of biologically active, macrocyclic lactone patulolide B (15), which was isolated in 67% yield with only a trace amount of trans-isomer 16 In our later studies 17b on the transition-metal-catalyzed reactions of diazo compounds derived from 10-dihydroartemisinin or 9-hydroxydeoxoartemisinin, the coupling reaction catalyzed by complex 1b also selectively afforded cis-alkenes (no trans-counterparts were detected), albeit in 37-40% yield.…”

Generation, Spectral Properties and Stability of p-Cation Radicals of (5,10,15,20-Tetraphenylporphyrinato)(chloro)rhodium(III)

“…Металлопорфирины (MP) проявляют каталити-ческую активность в реакциях окисления олефинов, [1] эпоксидирования алкенов, [2,3] окисления циклоалкенов [4] и карбаматов [5] и выступают моделями некоторых природных оксидоредуктаз, [6] инициируя устойчивый интерес к изучению собственной физикохимии. Большая роль в катализе принадлежит промежуточным окисленным формам MP.…”