Organolanthanide catalyst

An overview of the catalytically active M-L systems is presented in terms of both achiral and chiral reactions. Where deemed appropriate, reference is also made to organometallic and organolanthanide catalysts, as well as (briefly) H—X addition to C=0. 

Marks et al. s organolanthanide catalysts show a strong dependence on the substitution of the allene [99]. Terminal allenes 144 with three carbons in the tether deliver the tetrahydropyridines 145. 1,2-Disubstituted allenes with the same length of the tether lead to the vinylpyrrolines 146 (Scheme 15.45). 

Examples of cyclization through alkene insertion of a metal-nucleophile intermediate (Scheme 3, intermediate F) using organolanthanide catalysts, (Cp LaHfe, have been reported recently (equation 132), although turnover numbers rather than synthetic yields were reported.263... 

Coordination polymerization of dienes has progressed significantly within the last decade. Selective polymerization of 1,3-dienes is reinforced by conventional transition metal catalysts and by new organolanthanide catalysts. Nonconjugated dienes also polymerize selectively to produce polymers with cyclic units or vinyl pendant groups. Living polymerization of dienes has become common, which enabled preparation of block copolymers of dienes with alkenes and other monomers. Another new topic in this field is the polymerization of allenes and methylenecycloalkanes catalyzed by late transition metal complexes. These reactive dienes and derivatives provide polymers with novel structure as well as functionalized polymers. The precision polymerization of 1,2-, 1,3-, and l,n-dienes, achieved in recent years, will be developed to construct new polymer materials with olefin functionality. 

Polymerization of isoprene in the presence of organolanthanide catalysts under the action of microwave irradiation has been performed by Barbier-Baudry et al. 

With the aim of developing chiral organolanthanide catalysts for enantioselective transformations, the same group modified the aw a-lanthanocene framework in eomplexes 27 with a chiral group. The new catalytie precursors consist of Ci-symmetric octahydrofluorenyl complexes bearing an enantio-merically pure ( )-menthyl moiety in the lower Cp ring. Figure 6.2 depicts their structure. 

Organolanthanide catalysts provide a new alternative to traditional, late transition metal-based catalysts for selective hydrosilylation of alkenes and alkynes (for recent reviews, see (105)). Mechanistically, the transformation is characteristic of early transition metal-catalyzed reaction. However, it is worth... 

Baudry-Barbier, D. Camus, E. Dormond, A. Visseaux, M. Homogeneous organolanthanide catalysts for the selective polymerization of styrene without aluminium cocatalysts. Appl. Organomet. Chem. 1999,73,813-817. 

Organolanthanide catalysts, such as the divalent samarium complex, trivalent organolanthanide alkyls, lanthanide aryloxides, alkoxides, guanidinates, and thiolates,... 

Dudnik, A. S. Weidner, V. L. Motta, A. Delferro, M. Marks, T. J. Atom-efficient regioselective 1,2-dearomatization of functionalized pyridines by an earth-abundant organolanthanide catalyst. Nat. Chem. 2014, 6, 1100-1107. 

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