- Rhodium(I)-catalyzed domino asymmetric ring opening/enantioselective isomerization of oxabicyclic alkenes with water
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Water-induced asymmetric ring opening: Enantio-enriched 2-hydroxy-1-tetralones are formed from oxabicyclic alkenes through a novel RhI-catalyzed domino reaction. The proposed mechanism involves water-induced asymmetric ring opening to generate chiral trans-1,2-diol intermediates and subsequent enantioselective isomerization (see scheme). Copyright
- Tsui, Gavin C.,Lautens, Mark
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supporting information; experimental part
p. 5400 - 5404
(2012/07/03)
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- Hyperaromatic stabilization of arenium ions
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Benzene-cis- and trans-1,2-dihydrodiols undergo acid-catalyzed dehydration at remarkably different rates: kcis/ktrans = 4500. This is explained by formation of a β-hydroxycarbocation intermediate in different initial conformations, one of which is stabilized by hyperconjugation amplified by an aromatic no-bond resonance structure (HOC6H6 + HOC6H5 H+). MP2 calculations and an unfavorable effect of benzoannelation on benzenium ion stability, implied by pKR measurements of -2.3, -8.0, and -11.9 for benzenium, 1-naphthalenium, and 9-phenanthrenium ions, respectively, support the explanation.
- Kudavalli, Jaya S.,Boyd, Derek R.,Coyne, Dara,Keeffe, James R.,Lawlor, David A.,MacCormac, Aoife C.,More O'Ferrall, Rory A.,Rao, S. Nagaraja,Sharma, Narain D.
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supporting information; experimental part
p. 5550 - 5553
(2011/02/27)
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- Bio-inspired arene cis-dihydroxylation by a non-haem iron catalyst modeling the action of naphthalene dioxygenase
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Reported in this paper is the first example of a biomimetic iron complex, ([FeII(TPA)(NCMe)2]2+ (TPA = tris(2-pyridylmethyl)amine), that catalyses the cis-dihydroxylation of an aromatic double bond, mimicking the action of
- Feng, Yan,Ke, Chun-Yen,Xue, Genqiang,Que Jr., Lawrence
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body text
p. 50 - 52
(2009/03/11)
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- Biotransformation of phenanthrene and 1-methoxynaphthalene with Streptomyces lividans cells expressing a marine bacterial phenanthrene dioxygenase gene cluster.
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The phdABCD gene cluster in a marine bacterium Nocardioides sp. strain KP7 codes for the multicomponent enzyme phenanthrene dioxygenase. phdA encoding an iron-sulfur protein large subunit alpha, phdB encoding its small subunit beta, phdC encoding ferredoxin, and phdD encoding ferredoxin reductase, were replaced in such a way that the termination codons of the preceding open reading frames were overlapped with the initiation codons of the following genes. This manipulated phdABCD gene cluster was positioned downstream of the thiostrepton-inducible promoter PtipA in a high-copy-number vector pIJ6021, and introduced into the gram-positive, soil-inhabiting, filamentous bacterium Streptomyces lividans. The recombinant S. lividans cells converted phenanthrene into a cis-diol form, which was determined to be cis-3,4-dihydroxy-3,4-dihydrophenanthrene by its UV spectral data as well as HPLC property, using the authentic sample for comparison. This biotransformation proceeded very efficiently; 200 microM and 2 mm of phenanthrene were almost completely converted to its cis-diol form in 6 h and 32 h, respectively. In addition, the S. lividans cells carrying the phdABCD gene cluster were found to transform 1-methoxynaphthalene to two products, which were identified to be 8-methoxy-2-naphthol in addition to 8-methoxy-1,2-dihydro-1,2-naphthalenediol by their EI-MS, 1H- and 13C-NMR spectral data.
- Chun,Ohnishi,Misawa,Shindo,Hayashi,Harayama,Horinouchi
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p. 1774 - 1781
(2007/10/03)
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- Bioconversion of substituted naphthalenes to the corresponding 1,2-dihydro derivatives by Escherichia coli recombinant strains
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1,2-dihydroxynaphthalenes are produced by bioconversion of the corresponding hydrocarbons using Escherichia coli recombinant strains containing the naphthalene dioxygenase and dehydrogenase genes cloned from pseudomonas fluorescens N3. Conversions are lead by a two step procedure without isolation of the dihydrodiol intermediate. Conversion rates depend on the position and nature of the naphthalene substituent.
- Di Gennaro, Patrizia,Bestetti, Giuseppina,Galli, Enrica,Orsini, Fulvia,Pelizzoni, Francesca,Sello, Guido
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p. 6267 - 6270
(2007/10/03)
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- Dioxygenase-catalysed oxidation of dihydronaphthalenes to yield arene hydrate and cis-dihydro naphthalenediols
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Biotransformation of 1,2- and 1,4-dihydronaphthalene substrates, using growing cultures of Pseudomonas putida UV4, resulted in dioxygenase-catalysed benzylic monohydroxylation, cis-tetrahydro diol and cis-dihydro diol formation, trihydroxylation and dehydrogenation. The arene hydrates, (R)-1,2-dihydronaphthalen-1-ol 5 and (R)-1,4-dihydronaphthalen-1-ol 7, were isolated as enantiopure metabolites while 1,2-dihydronaphthalen-2-ol 8 was found in almost racemic form. The structure, enantiopurity and absolute stereochemistry of these arene hydrates of naphthalene were confirmed by chemical synthesis. Deuterium labelling studies, and the use of enantiomerically pure arene hydrates 5 and 7 as substrates, were used to establish the metabolic pathways for the formation of (1R,2S)-1,2-dihydronaphthalene-1,2-diols 2, from both 1,2-dihydronaphthalene 3 and 1,4-dihydronaphthalene 6 substrates.
- Boyd, Derek R.,Sharma, Narain D.,Kerley, Nuala A.,McMordie, R. Austin S.,Sheldrake, Gary N.,Williams, Paul,Dalton, Howard
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- Stereospecific Benzylic Hydroxylation of Bicyclic Alkenes by Pseudomonas putida: Isolation of (+)-R-1-Hydroxy-1,2-dihydronaphthalene, an Arene Hydrate of Naphthalene from Metabolism of 1,2-Dihydronaphthalene
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Metabolism of the bicyclic alkenes 1,2-dihydronaphthalene, indene, and 1,2-benzocyclohepta-1,3-diene by a mutant strain of Pseudomonas putida yields benzylic monols (exclusively with R configuration) as metabolites and vicinal cis diols as minor products having an excess of the S configuration at the benzylic position.
- Boyd, Derek R.,McMordie, R. Austin S.,Sharma, Narain D.,Dalton, Howard,Williams, Paul,Jenkins, Richard O.
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p. 339 - 341
(2007/10/02)
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- Reduction of ortho-Quinones to Dihydrodiols
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1,2-Naphthaquinone, 5-bromo-1,2-naphthaquinone and dibenzanthracene-3,4-quinone in the form of dibromo-intermediates were reduced to a mixture of cis- and trans-diols by the action of sodium borohydride in ethanol.An alternative synthesis of trans-3,4-dihydroxy-3,4-dihydrodibenzanthracene is also reported.
- Kundu, Nitya G.
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p. 1920 - 1923
(2007/10/02)
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