Highly diastereofacial selective chelation of a phosphite-containing .alpha.,.beta.-unsaturated ketone system to the Fe(CO)2 group

Zhang, Wei Yuan.; Jakiela, Dennis J.; Maul, Andre.; Knors, C.; Lauher, Joseph W.; Helquist, Paul; Enders, Dieter

doi:10.1021/ja00222a026

Cited by 41 publications

(17 citation statements)

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“…The conversions and yield and ee values of products 13 c – j are comparable with the results obtained for the lower homologues 8 c – j ; therefore, 12 is a suitable propionyl anion donor in reactions catalyzed by Ao:DCPIP OR. The absolute configuration of products 8 d , 8 g , 8 h , 13 d 13 g and 13 h show that, with acceptors 7 d , 7 g or 7 h , the enzyme is ( S )‐stereoselective independently from the use of 1 or 12 as donor . These results are congruent with those we previously reported using aromatic aldehydes as acceptors …”

Section: Resultsmentioning

confidence: 99%

Enzymatic Cross‐Benzoin‐Type Condensation of Aliphatic Aldehydes: Enantioselective Synthesis of 1‐Alkyl‐1‐hydroxypropan‐2‐ones and 1‐Alkyl‐1‐hydroxybutan‐2‐ones

et al. 2018

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Benzoin-type reactions have been intensively exploited as a synthetic strategy for the preparation of a-hydroxy ketones. Thiamine diphosphate (ThDP) dependent enzymes are excellent catalysts for asymmetric versions of such reaction types. In particular, in cross-benzoin condensations of aromatic reactants and mixed aromatic/aliphatic reactions, use of these enzymes has resulted in high levels of chemo-, regio-and stereoselectivity. The present work, which confirms this trend for aliphatic reactants, outlines results obtained in the formal cross-benzoin-type condensation of the 'umpoled' acetaldehyde and propionaldehyde with various aliphatic aldehydes catalyzed by the ThDP-dependent enzyme acetoin:dichlorophenolindophenol oxidoreductase (Ao:DCPIP OR). In these reactions, 3-hydroxy-3-methylbutan-2-one (methylacetoin) was used as the activated acetaldehyde donor, while 4-hydroxy-4-methylhexan-3-one was employed for the first time as the precursor of activated propionaldehyde. With the exception of 3hydroxypentan-2-one and 3-hydroxyhexan-2-one, which were obtained in almost racemic form by the condensation of methylacetoin with propanal and butanal, respectively, all other products achieved from reactions performed using the same donor with more hindered aldehyde acceptors were obtained with high conversions (89-99%) and in good to high enantiomeric excess (72-99% ee). In a similar way, high conversions (75-99%) and good ee (76-99%) were observed in reactions performed with the same set of aldehyde acceptors, but using 4-hydroxy-4-methylhexan-3-one as propionyl anion donor. This is the first time that most of the products described herein have been prepared via benzoin-type condensation.

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Section: Resultsmentioning

confidence: 99%

Enzymatic Cross‐Benzoin‐Type Condensation of Aliphatic Aldehydes: Enantioselective Synthesis of 1‐Alkyl‐1‐hydroxypropan‐2‐ones and 1‐Alkyl‐1‐hydroxybutan‐2‐ones

et al. 2018

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“…[75] Investigations were carried out with a,b-unsaturated compounds because of their known ability to form reasonably stable and characterizable metal complexes. Synthesis of (R)-(À)-coniine.…”

Section: 4-additionsmentioning

confidence: 99%

“…diastereofacial selective coordination of the alkene. [75] Investigations were carried out with a,b-unsaturated compounds because of their known ability to form reasonably stable and characterizable metal complexes. Reaction of phosphitefunctionalized enone 83 with the iron complex 84 under substitution of benzylidene acetone led to the corresponding iron complex.…”

Section: 4-additionsmentioning

confidence: 99%

Removable Directing Groups in Organic Synthesis and Catalysis

2011

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Directing groups have been widely used in recent years to achieve control over all aspects of reaction selectivity in a wide range of transformations involving transition-metal catalysis and organometallic reagents. In cases when the existing functional group within a substrate is unsuited to achieve efficient intramolecular delivery of a reagent or catalyst, the specific introduction of an appropriately designed removable reagent-directing group can be a solution to this problem. In this Review we give an overview of the state of the art in this area, including the stoichiometric and catalytic use of directing groups.

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“…Eine dirigierte konjugierte Addition an Phosphit‐funktionalisierte Enone 83 wurde von Helquist et al. entwickelt (Schema ) 75. Dazu werden die Substrate 83 durch Umsetzung mit dem Eisenkomplex 84 und Verdrängung des Benzylidenaceton‐Liganden chelatartig über Enon und Phosphitfunktion an das Eisenzentrum gebunden.…”

Section: Stöchiometrischer Einsatz Von Entfernbaren Dirigierenden unclassified

Entfernbare dirigierende Gruppen in der organischen Synthese und Katalyse

2011

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Dirigierende Gruppen haben in den vergangenen Jahren breite Anwendung gefunden, um Reaktionsselektivitäten in einem breiten Spektrum an übergangsmetallkatalysierten Reaktionen und Reaktionen metallorganischer Reagentien zu steuern. In Fällen, in denen die im Substrat vorhandenen funktionellen Gruppen nicht geeignet sind, um eine effiziente intramolekulare Reagens‐ oder Katalysator‐Steuerung zu ermöglichen, kann das gezielte Einbringen von maßgeschneiderten und wieder entfernbaren reagensdirigierenden Gruppen eine Lösung für dieses Problem bieten. In diesem Aufsatz geben wir eine Überblick zum Stand der Forschung auf diesem Gebiet und schließen dabei sowohl den stöchiometrischen wie den katalytischen Einsatz dirigierender Gruppen ein.

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Highly diastereofacial selective chelation of a phosphite-containing .alpha.,.beta.-unsaturated ketone system to the Fe(CO)2 group

Cited by 41 publications

References 0 publications

Enzymatic Cross‐Benzoin‐Type Condensation of Aliphatic Aldehydes: Enantioselective Synthesis of 1‐Alkyl‐1‐hydroxypropan‐2‐ones and 1‐Alkyl‐1‐hydroxybutan‐2‐ones

Enzymatic Cross‐Benzoin‐Type Condensation of Aliphatic Aldehydes: Enantioselective Synthesis of 1‐Alkyl‐1‐hydroxypropan‐2‐ones and 1‐Alkyl‐1‐hydroxybutan‐2‐ones

Removable Directing Groups in Organic Synthesis and Catalysis

Entfernbare dirigierende Gruppen in der organischen Synthese und Katalyse

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