New Facts on the Stereoselectivity of Monobromocarbenoid Additions to Cyclic Alkenes
作者:Eckehard V. Dehmlow、Horst Lustinetz
DOI:10.1002/jlac.199619961217
日期:1996.12
The monobromocarbenoid derived from CH2Br2 and NaN(SiMe3)2 gives only endo adducts 4, 5, and 6 with 1,5-cyclooctadiene, but shows no selectivity with 1,3-cyclooctadiene. A literature report of a high endo adduct preference of cyclooctene cannot be duplicated, but cyclodecene is converted to 3 with 100% selectivity. Bromocarbenoid adducts 11, 13, and 14 of norbornene and norbornadiene are reported.
Reaction of cyclopropylcarbene–metal complexes with nucleophiles, halogens and HX
作者:Margaret D. Reid、Liz Tirado、Jianwei Zhang、Nwamara Dike、James W. Herndon
DOI:10.1016/j.jorganchem.2005.07.044
日期:2005.12
The reaction of halogens, pseudohalogens, and HX with cyclopropyl(phenylthio)carbene-chromium complexes leads to the formation of 1,4-dihalo-1-thiophenyl-1-butene systems with a moderate-high degree of stereocontrol in the formation of the alkene. A mechanism involving electrophilic activation of the carbene complex followed by nucleophilic attack at the cyclopropane carbon has been proposed.
This report showcases the stereospecific and modular synthesis of vinyl cyclopropanes in less than 30 min at room temperature, employing air-stable dinuclear PdI catalysis.