A mechanistic study of the reductive coupling of acetone with uranium compounds

Ephritikhine, Michel; Maury, Olivier; Villiers, Claude; Lance, M.; Nierlich, Martine

doi:10.1039/a802672f

Cited by 23 publications

(14 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The above-mentioned mechanism involving the pinacolate intermediates is supported by these studies. Thus, the uranium pinacolates of benzophenone 40 and acetone 41,42 have been isolated and characterized as intermediates, which undergo the deoxygenation to produce the corresponding alkenes upon heating the reaction mixtures at reflux temperatures.…”

Section: Methodsmentioning

confidence: 99%

The McMurry Coupling and Related Reactions

Takeda

Tsubouchi

2013

Organic Reactions

View full text Add to dashboard Cite

The McMurry coupling reaction has been recognized as one of the most efficient methods for the synthesis of alkenes from carbonyl compounds. This reaction can be applied to the preparation of various alkenes that are otherwise difficult to prepare. For example, sterically congested tetrasubstituted alkenes as well as medium to large membered rings involving natural products may be accessed via this process. This coupling utilizes various low‐valent titanium reagents generated by the reduction of titanium (III or IV) chloride with K, Zn, LiAlH 4 , C 8 K, amongst others. Furthermore, a variety of low‐valent metal species other than titanium, including aluminum, zirconium, niobium, molybdenum, indium, tungsten, and samarium, have also been found to promote the reductive coupling of carbonyl compounds. The scope and limitations of these reagent systems are reviewed in this chapter, together with the stereochemistry and reaction mechanism. This reaction is categorized into four coupling modes: i) homocoupling giving symmetrical alkenes, ii) mixed coupling giving unsymmetrical alkenes, iii) intramolecular coupling giving cycloalkenes, and iv) tandem coupling giving cyclic polyenes. Characteristics of these reaction modes are described briefly. A selection of synthetic applications are reviewed, including examples of the preparation of sterically congested and strained alkenes, medium to large‐ring compounds, biologically active targets, as well as substrates applicable in material science. Experimental conditions used for this versatile process are summarized to assist the choice of suitable conditions.

show abstract

Section: Methodsmentioning

confidence: 99%

The McMurry Coupling and Related Reactions

Takeda

Tsubouchi

2013

Organic Reactions

View full text Add to dashboard Cite

show abstract

“…Hydrolysis of the metallapinacolate compounds produced 1,2-diols while deoxygenation of the metallapinacolates into alkenes was observed at high temperatures. However, the mechanism of the rate-limiting deoxygenation step remains unclear and the nature of the amalgam greatly affected this process, which could only be achieved using Li(Hg) in refluxing THF [134,135].…”

Section: Mechanisms Of Pinacol and Mcmurry Coupling Reactionsmentioning

confidence: 99%

“…Moreover, the deoxygenation of metallapinacolate intermediates to give alkenes has been demonstrated in uranium-mediated reductive coupling of aliphatic and aromatic ketones [133][134][135]. Villiers Regardless of the amalgam used, reaction of acetone with UCl 4 first produced 66 as the intermediate [135]; 66 was formed by dimerization of the ketyl species Cl 3 U(OCMe 2 • ), which was trapped with Ph 3 SnH. Hydrolysis of the metallapinacolate compounds produced 1,2-diols while deoxygenation of the metallapinacolates into alkenes was observed at high temperatures.…”

Section: Mechanisms Of Pinacol and Mcmurry Coupling Reactionsmentioning

confidence: 99%

Low-Valent Titanium-Mediated Reductive Coupling of Carbonyl Compounds

Ladipo¹

2006

COC

View full text Add to dashboard Cite

This account describes recent organic synthesis applications and developments in mechanistic understanding of low-valent titanium-mediated reductive coupling of carbonyl compounds. Pinacol and McMurry coupling reactions are among the most powerful methods for constructing carbon-carbon bonds, and have served as the key step in the synthesis of various natural and synthetic products. The range and selectivity of low-valent titanium reagents that mediate pinacol and McMurry reactions are discussed. The nature of their active species is discussed in conjunction with relevant chemistry of well-characterized low-valent titanium complexes, all of which serve to inform current understanding of the reaction mechanisms.

show abstract

“…Several metallopinacols have been isolated from the reaction of acetone with UCl 4 and M(Hg); their structures and their eventual transformation into Me 2 CbCMe 2 were found to be strongly influenced by the molar ratio of the reactants, the nature of the amalgam used, Li(Hg) or Na(Hg), and the salts formed, LiCl or NaCl (Scheme 6.13) [277,278].…”

Section: Characterization Of the Pinacolate Intermediatesmentioning

confidence: 99%