Synthesis and transformations of metallacycles. 26. Cp2ZrCl2-Catalyzed cycloalumination of substituted allenes with Et3Al

Catalytic cycloalumination of 1-alkyl(phenyl)allenes with triethylaluminum (5 mol.% of Cp₂ZrCl₂ as the catalyst, 20 °C, 4 h, hexane) afforded methylene- and alkyl(benzyl)idene-substituted alumacyclopentanes.     

Synthesis and transformation of metallacycles. 25. On a mechanism of the Ni(acac)2-catalyzed conversion of 3-alkyl-1-ethylalumacyclopentanes into 1,1-disubstituted cyclopropanes

The reactions of 3-alkyl-1-ethylalumacyclopentanes with allyl halides in the presence of Ni(acac)₂ as a catalyst were studied by dynamic NMR spectroscopy. Under the action of Ni complexes, alumacyclopentanes initially undergo intramolecular hydride transfer to give but-3-enyl(ethyl)aluminum hydrides and then react with the starting allyl halide, yielding but-3-enyl(ethyl)aluminum halides. Subsequent intramolecular carboalumination affords the corresponding 1,1-disubstituted cyclopropanes.