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The search for efficient and selective routes for the synthesis of chiral aminocyclopropane derivatives is of great interest and importance as these structures are important components of biologically active natural products and pharmaceuticals. We herein report the enantioselective intermolecular hydroamination of substituted cyclopropenes with various amines catalyzed by chiral half-sandwich rare-earth-metal complexes. This method constitutes a 100 % atom-efficient route for the synthesis of a variety of chiral α-aminocyclopropane derivatives in high yields (up to 96 %) and excellent stereoselectivity (up to >20:1 d.r. and 99 % ee) under mild reaction conditions (25 °C). [ABSTRACT FROM AUTHOR]

The catalytic CH addition of pyridines to allenes has been achieved for the first time by using a half-sandwich scandium catalyst, thus constituting a straightforward and atom-economical route for the synthesis of alkenylated pyridine derivatives. The reaction proceeded regio- and stereoselectively, affording a new family of alkenylated pyridine compounds which are otherwise difficult to synthesize. A cationic Sc-η2-pyridyl species was isolated and confirmed to be a key catalyst species in this transformation. [ABSTRACT FROM AUTHOR]

A series of silylene-linked cyclopentadienyl-phosphido rare earth alkyl and hydride complexes of type Me2Si(C5Me4)(PR′)LnR (Ln=Y, Yb, Lu; R′=Ph, Cy, C6H2tBu3-2,4,6; R=CH2SiMe3, H) have been synthesized and structurally characterized, and their activity in ethylene polymerization and olefin hydrosilylation has been studied. These complexes represent the first examples of rare earth alkyl and hydride complexes bearing cyclopentadienyl-phosphido ligands, which are in sharp contrast both structurally and chemically with the analogous cyclopentadienyl-amido and metallocene complexes. [Copyright &y& Elsevier]

Half‐sandwich rare‐earth dialkynyl complexes are of much interest in both structure and reactivity but have remained much underexplored to date. Here we report the synthesis and transformation of a new family of half‐sandwich dialkynyl complexes bearing the C5Me4SiMe3 ligand, which exhibited diverse structural features depending on metal ion size, alkyne substituent and with or without THF coordination. The acid‐base reactions between half‐sandwich rare earth dialkyl complexes (C5Me4SiMe3)Ln(CH2SiMe3)2(THF) (Ln=Sc, Y, Lu) and two equivalents of terminal alkynes such as phenylacetylene and trimethylsilylacetylene in THF generally gave the corresponding THF‐coordinated monomeric rare earth dialkynyl complexes, which upon recrystallization from toluene yielded further aggregated alkynyl complexes with partial or full dissociation of the THF ligands. In the case of phenylacetylene, trimeric yttrium and lutetium hexaalkynyl complexes were formed, in which each pair of the metal atoms was bridged by two alkynyl ligands in solid state but the alkynyl ligands underwent rapid site exchange in toluene solution. In the case of trimethylsilylacetylene with yttrium and lutetium, dimeric tetraalkynyl complexes bearing two terminal and two bridging alkynyl ligands were obtained from toluene. In contrast, recrystallization of the scandium trimethylsilylacetylide complex from toluene induced alkynyl coupling and yielded dimeric scandium complex with one butatrienediyl and two alkynyl bridging ligands. Upon dissolution in THF, all the aggregated alkynyl/butatrienediyl complexes were rapidly reconverted to the monomeric dialkynyl complexes as a result of THF coordination to the rare earth metal atoms. [ABSTRACT FROM AUTHOR]

This article focuses on the catalytic addition of terminal alkynes to carbodiimides by half-sandwich rare earth metal complexes. It is reported in this article that the half-sandwich rare earth metal complexes, which bear silylene-linked cyclopentadienyl-amido ligands act as an excellent catalyst for the addition of terminal alkynes to carbodiimides. In this process a rare earth metal amidinate species has been confirmed to be a true catalytic species. The researchers conclude that the catalytic addition of terminal alkynes to carbodiimides has been achieved for the first time by use of half-sandwich rare earth metal complexes as a catalyst.

Reports on a novel organolanthanide catalyst system for the regio- and stereoselective head-to-head (Z)-dimerization of terminal alkynes. Recovery and reuse of the catalyst system; Reactivity of a series of half-metallocene alkyl complexes; High head-to-head (Z)-selectivity for the dimerization of of phenylacetylene by the lutetium anilido complexes.

Heteromultimetallic hydride complexes consisting of both rare-earth and d-transition metals are expected to exhibit unique reactivity because they have potential to show the synergistic effect of the substantially different types of metal centers. Here we report the reactions of rare-earth/ruthenium heterobimetallic dihydride complexes [Cp*Lu(THF)( μ -H) 2 ( μ - η 1 : η 1 -CHRP(CH 2 R) 2 )RuCp*] and [(C 5 Me 4 SiMe 3 )Y(DME)( μ -H) 2 ( μ - η 1 : η 1 -C 6 H 4 PPh 2 )RuCp*] (R = H, Me; Cp* = C 5 Me 5 ) with carbon monoxide. C–O bond cleavage and C–C bond formation, as well as P–C bond cleavage of the phosphine ligand occurred through the cooperation of two different metal centers. Dependence of the reaction pattern on the substituents of the phosphine ligands was also observed. [ABSTRACT FROM AUTHOR]