Synthesis, Structural Characterization, and Catalytic Activity of Indenyl Tris( N ‐pyrrolyl)phosphine Complexes of Ruthenium

Branching out: redox strategies towards the synthesis of acyclic α-tertiary ethers

Acyclic α-tertiary ethers represent a highly prevalent functionality, common to high-value bioactive molecules, such as pharmaceuticals and natural products, and feature as crucial synthetic handles in their construction. As such their synthesis has become an ever-more important goal in synthetic chemistry as the drawbacks of traditional strong base- and acid-mediated etherifications have become more limiting. In recent years, the generation of highly reactive intermediates via redox approaches has facilitated the synthesis of highly sterically-encumbered ethers and accordingly these strategies have been widely applied in α-tertiary ether synthesis. This review summarises and appraises the state-of-the-art in the application of redox strategies enabling acyclic α-tertiary ether synthesis.

Ferrocenium complex aided O-glycosylation of glycosyl halides

A new strategy for the activation of glycosyl halide donors to be utilized in glycosylation reactions is presented, utilizing the ferrocenium (Fc) complexes [FcB(OH)₂]SbF₆ and FcBF₄ as promoters. The scope of the new system has been investigated using glycosyl chloride and glycosyl fluoride donors in combination with common glycosyl acceptors, such as protected glucose. The corresponding glycosylation products were formed in 95 to 10% isolated yields with α/β ratios ranging from 1/1 to β only (2 to 14 h reaction time at room temperature, 40 to 100% ferrocenium promoter load).

Ferrocenium complexes as a new, tunable platform for O-glycosylation reactions are introduced.

Indenylmetal Catalysis in Organic Synthesis

Synthetic organic chemists have a long-standing appreciation for transition metal cyclopentadienyl complexes, of which many have been used as catalysts for organic transformations. Much less well known are the contributions of the benzo-fused relative of the cyclopentadienyl ligand, the indenyl ligand, whose unique properties have in many cases imparted differential reactivity in catalytic processes toward the synthesis of small molecules. In this Review, we present examples of indenylmetal complexes in catalysis and compare their reactivity to their cyclopentadienyl analogues, wherever possible.