Reagents for Carbonyl Methylenation in Organic Synthesis

Structural Elucidation of the Illustrious Tebbe Reagent

“…The Tebbe reagent, [Cp 2 Ti(μ 2 -Cl)(μ 2 -CH 2 )AlMe 2 ] ( 1 ), stands as a historic milestone in the field of organometallic chemistry. Its ability to transfer a methylene group to organic species via metallo-Wittig chemistry was later extended to other methylidene transfer reactions − which proceed through a similar metathesis. This well-known process ultimately culminated in the 2005 Nobel Prize being awarded to Chauvin, Grubbs, and Schrock. − Although reagent 1 was first reported by Tebbe and co-workers in 1978, the original experiments were performed much earlier in the summer of 1974 at the DuPont Central Research Division .…”

Total Synthesis of (−)‐Dolastatrienol

“…However, after 21 a was silylated as 21 b , under the same reaction conditions, an α‐ketol rearrangement occurred instead of methylenation to generate [5,8,5]‐tricyclic 29 . Methylenation using the Peterson, Tebbe, Petasis, Nysted, or Lombardo reagents also failed to induce any reaction 21. The successful Wittig reactions with model substrates 25 and 27 , but not with the tricyclic 21 b , clearly showed that the failure was due to the presence of the additional, distal five membered ring.…”

Direct Access to Unique C‐5’‐Acyl Modified Nucleosides through Liebeskind–Srogl Cross‐Coupling Reaction

“…[14] By contrast, applications of the Liebeskind-Srogl cross-coupling for the formation of C-acyl-functionalized biomolecules are more scarce [15] and to the best of our knowledge this reaction has never been applied to prepare C-5'-acylnucleosides (Figure 1d). Apart from their intrinsic potential activities, these derivatives represent versatile building blocks for bioactive diversification through olefination, [16] deoxyfluorination [17] or reduction methods. In the latter case, C-5'-acylnucleosides could be further transformed as phosphoramidite building blocks for the synthesis of modified oligonucleotides.…”