Highly Regio- and Diastereoselective Chromium(0)-Catalysed Cyclopropanation of 1-Alkoxy-1,3-dienes with Diazo Compounds
作者:Norbert D. Hahn、Martin Nieger、Karl Heinz Dötz
DOI:10.1002/ejoc.200300687
日期:2004.3
Pentacarbonyl(η2-cis-cyclooctene)chromium(0) (1) is an efficient catalyst for diazo decomposition and selective [2+1]-cycloaddition reactions of the resulting carbene intermediates with electron-rich dienes. The cyclopropanation of 1-alkoxy-1,3-butadienes 4−8 with 9-diazo-9H-fluorene (2) yields vinylspirocyclopropanes 9−13 in good to excellent yields, as single regioisomers arising from carbene transfer