| 1. |
- Dunås, Petter, 1990, et al.
(författare)
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Selective Iron-Mediated C- and O-Addition of Phenolic Nucleophiles to a Cyclohexadiene Scaffold Using Renewable Precursors
- 2019
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Ingår i: ACS Sustainable Chemistry & Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 7:7, s. 7155-7162
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Tidskriftsartikel (refereegranskat)abstract
- Renewable phenols have been investigated as nucleophiles for the addition to a cationic cyclohexadienyl iron carbonyl scaffold. Benign conditions compatible with solvents such as ethanol and water were developed, and for the first time, selective C- or O-addition could be achieved. In addition, a novel atom-economic approach to forming the C-addition products directly from the neutral precursor complex in a single step using a catalytic acid is described. The formed C-addition product could then be selectively demetalated to form one of two different product classes, a functionalized arene or a cyclohexadiene.
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| 2. |
- Paterson, Andrew, 1988, et al.
(författare)
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Palladium Catalyzed Stereoselective Arylation of Biocatalytically Derived Cyclic 1,3-Dienes: Chirality Transfer via a Heck-Type Mechanism
- 2020
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Ingår i: Organic Letters. - : American Chemical Society (ACS). - 1523-7052 .- 1523-7060. ; 22:6, s. 2464-2469
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Tidskriftsartikel (refereegranskat)abstract
- Microbial arene oxidation of benzoic acid with Ralstonia eutropha B9 provides a chiral highly functionalized cyclohexadiene, suitable for further structural diversification. Subjecting this scaffold to a Pd-catalyzed Heck reaction effects a regio- and stereoselective arylation of the cyclohexadiene ring, with 1,3-chirality transfer of stereogenic information installed in the microbial arene oxidation. Quantum chemical calculations explain the selectivity both by a kinetic preference for the observed arylation position and by reversible carbopalladation in competing positions. Further product transformation allowed the formation of a tricyclic ketone possessing four stereogenic centers. This demonstrates the capability of the method to introduce stereochemical complexity from planar nonchiral benzoic acid in just a few steps.
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| 3. |
- Ten Broeke, M., et al.
(författare)
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Tricarbonyliron(0) complexes of bio-derived η4 cyclohexadiene ligands: An approach to analogues of oseltamivir
- 2015
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Ingår i: Journal of Organometallic Chemistry. - : Elsevier BV. - 0022-328X. ; 799-800, s. 19-29
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Tidskriftsartikel (refereegranskat)abstract
- We have prepared novel [η4] and [η5]+ tricarbonyliron complexes from an unusual enantiopure cyclohexadiene ligand that possesses a quaternary stereocentre; this in turn is prepared through biotransformation of an aromatic ring. The cyclohexadiene ligand initially possessed two hydroxyl groups, both of which could be substituted with other functionality by means of an overall [η4] → [η5]+ → [η4] → [η5]+ → [η4] sequence. From six novel tricarbonyliron complexes which have been prepared, three have been characterised by x-ray crystallography. The reaction sequence we describe is potentially of relevance to the synthesis of analogues of the anti-influenza drug oseltamivir. In addition, the failure of an attempted addition of a bulky nitrogen nucleophile to an [η5]+ complex sheds light on the limits of reactivity for such additions. Thus, two bulky nucleophiles which are each known to add successfully to unencumbered [η5]+ complexes seemingly cannot be added sequentially to adjacent positions on the cyclohexadiene ligand.
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