A highly efficient protocol for the large-scale oxidative cyclization of 1,5-dienes is described. This convenient ruthenium(VIII)-catalyzed (0.2 mol%) cyclization reaction allows the preparation of cis-2,5-disubstituted tetrahydrofurans in high yields (up to 92%) and excellent diastereomeric ratio (>95:5 dr). This simple and reliable method is insensitive to moisture and air and can, therefore, be carried out in an open reaction vessel.
A Highly Efficient Procedure for Ruthenium Tetroxide Catalyzed Oxidative Cyclizations of 1,5-Dienes
作者:Stefanie Roth、Sabrina Göhler、Huan Cheng、Christian B. W. Stark
DOI:10.1002/ejoc.200500052
日期:2005.10
for the oxidative cyclization of 1,5-dienes, which generally allows for high yields and selectivities. A solid-supported terminal oxidant and a finely tuned solvent mixture have both been identified as critical factors for this high efficiency. As little as 0.2 mol-% ruthenium(III) chloride as a pre-catalyst for the rutheniumtetroxide generated in situ is required to accomplish oxidative cyclization
Synthesis and transformations of metallacycles 35. Joint cycloalumination of cyclic 1,2-dienes with disubstituted acetylenes and terminal allenes under the action of EtAlCl2 catalyzed by Ti and Zr complexes
作者:V. A. D’yakonov、R. K. Timerkhanov、T. V. Tyumkina、U. M. Dzhemilev
DOI:10.1007/s11172-009-0344-4
日期:2009.12
Catalytic intermolecular cycloalumination of cyclic 1,2-dienes with terminal allenes or disubstitutedacetylenes mediated by EtAlCl2 in the presence of complexes based on transition metals was accomplished. The yield of unsaturated bicyclic aluminacarbocycles was up to 85%.