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International audience; The readily available iron complex [CpFe(CO)2]2 (1) exhibits good catalytic activity in the hydrosilylation of aldehydes and ketones in the presence of diethoxymethylsilane. The procedure described is air-tolerant and applicable to a wide range of substrates

The preparation of a simple 1-oxa-spiro[2.4]heptane derivative is described. Observations made in the course of the synthesis show again that apparently minor structural modifications of the dienic substrate exert a strong influence on the ring-closing metathesis outcome and that the efficient construction of even simple but highly substituted systems by RCM may constitute a synthetic challenge.

A palladium-catalyzed coupling reaction of aryl bromides with vinylic acetates in the presence of tributyltin methoxide has been described. The a-arylation aldehyde product and the aryl ketone were obtained in the presence of P(t-Bu)3 and P(o-Tol)3, respectively.

A regio- and stereoselective synthesis of arylidene indenols has been developed. The key step involves a palladium-catalyzed tandem carbocyclization/Suzuki–Miyaura sequence.

Ring closing metathesis of sugar-derived 1,6 dienes is the key step for the construction of highly functionnalized cyclohexenes, precursors of branched cyclitols and aminocyclitols. The method has been used for a short synthesis of valiolamine.

Samarium diiodide and other lanthanide iodides are very efficient Lewis acid catalysts for numerous reactions such as Mukaiyama aldol and Michael reactions, preparation of enoxysilanes, cycloaddition reactions and ring opening of oxiranes by silylated nucleophiles or amines. Activities and selectivities of catalysts vary with the nature of the metal and the ligands for some reactions. Lanthanide iodides coordinated by a cyclopentadienyl ligand with an asymmetric center and an ether function on a pendant chain have been characterized and tested for catalysis: low enantioselectivities are observed for complexes with intramolecular coordination.

Sml2(THF)2 catalyzes the ring opening of epoxides by trimethylsilylazide, trimethylsilylcyanide and primary and secondary amines. High regioselectivities are observed in specific cases.

SmI2 presents catalystic activity for Diels-Alder reactions between cyclopentadiene or isoprene and various dienophiles, and for hetero Diels-Alder reactions.

SmI 2 is the precursor of efficient catalysts for the aldolisation reactions of aldehydes and ketones with enol silanes. α,β-unsaturated ketones give 1,4-addidtions selectively.

A sterically hindered 1,6-dienic system underwent clean ring-closing metathesis using Schrock's catalyst. The product was converted into new 5-membered branched cyclitols and is a potential precursor of other biologically relevant aminocyclitols.