Cobalt and iron complexes of chiral C1- and C2-terpyridines: Synthesis, characterization and use in catalytic asymmetric cyclopropanation of styrenes

Yeung, Chi Tung; Sham, Kiu Chor; Lee, Wing Sze; Wong, Wing Tak; Wong, Wai Yeung; Kwong, Hoi‐Lun

doi:10.1016/j.ica.2009.02.034

Cited by 37 publications

(11 citation statements)

References 29 publications

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“…The catalytic activity of several cobalt complexes of modified Schiff bases, [63][64][65] terpyridines, [66] nitrogen macrocycles, [67] pincer ligands [68] and polyoxometallates [69] was also reported. However, porphyrin ligands represent, along with Schiff bases, the most frequently used class of ligands to synthesise cobalt cyclopropanation catalysts.…”

Section: Cobalt-catalysed Reactionsmentioning

confidence: 99%

Cyclopropanation Reactions Mediated by Group 9 Metal Porphyrin Complexes

2011

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Keywords: Cyclopropanation / Diazo compounds / Porphyrins / Cobalt / Rhodium / IridiumThe one-pot reaction of diazo compounds with olefins represents a useful strategy to synthesise cyclopropanes, which are important both as starting materials for the synthesis of organic compounds and because of their intrinsic pharmaceutical properties. Herein we describe the catalytic activity of group 9 metal porphyrin complexes to cyclopropanate ole-

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Section: Cobalt-catalysed Reactionsmentioning

confidence: 99%

Cyclopropanation Reactions Mediated by Group 9 Metal Porphyrin Complexes

2011

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“…(1)] 2. Many transition‐metal complexes, especially those containing rhodium,3 copper,2e, 4 cobalt,5 iron,5f, k, 6 or ruthenium,7 have been employed to induce this type of transformation. Interestingly, one of the most commonly employed metals in homogenous catalysis, palladium, has scarcely been described as a catalyst for this process, in spite of the discovery of its application for this purpose in the mid sixties 8.…”

Section: Introductionmentioning

confidence: 99%

Stable N‐Heterocyclic Carbene (NHC)–Palladium(0) Complexes as Active Catalysts for Olefin Cyclopropanation Reactions with Ethyl Diazoacetate

Martı́n

Molina

Álvarez

et al. 2011

Chemistry A European J

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Abstract. The Pd(0) complexes NHCPdLn (NHC = N-heterocyclic carbene ligand; L = styrene for n = 2 or PR3 for n = 1) efficiently catalyze the olefin cyclopropanation using ethyl diazoacetate (EDA) as the carbene source with activities that improve any other previous described catalytic system based on this metal. Mechanistic studies have shown that all those catalyst precursors deliver in solution the same catalytic species (IPr)Pd(sty), a 14e, unsaturated intermediate that further reacts with EDA to afford (IPr)Pd(=CHCO2Et)(sty), from which cyclopropane is formed.

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“…[12] However, the study mainly focussed on synthesis and characterization of such complexes and lacks of generality and substrate scope since only cyclopropanation of styrene with ethyl diazoacetate was described. The most effective ligands for this cyclopropanation were found to be terpyridines L 3 -L 5 ; L 5 providing the highest enantiomeric excesses for this transformation (65 and 67 % ee for trans-and cis-cyclopropanes, respectively).…”

Section: Discussionmentioning

confidence: 99%