Tandem Catalysis: Generating Multiple Contiguous Carbon−Carbon Bonds through a Ruthenium-Catalyzed Ring-Closing Metathesis/Kharasch Addition
作者:Benjamin A. Seigal、Cristina Fajardo、Marc L. Snapper
DOI:10.1021/ja055806j
日期:2005.11.23
0], and [5.3.0] ring systems in one step from the appropriately functionalized acyclic precursors. For substrates where the intramolecular Kharasch addition fails, an intermolecularKharasch addition is possible. By combining the intra- and intermolecularKharasch additions with RCM, three new contiguous carbon-carbon bonds with multiple stereocenters can be generated by the ruthenium catalyst in a controlled
Scope of the directed dihydroxylation: application to cyclic homoallylic alcohols and trihaloacetamides
作者:Timothy J. Donohoe、Lee Mitchell、Michael J. Waring、Madeleine Helliwell、Andrew Bell、Nicholas J. Newcombe
DOI:10.1039/b303081d
日期:——
The synthesis and directed dihydroxylation of a range of cyclic alkenes was investigated. Both homoallylic alcohols and homoallylic trihaloacetamides were found to be efficient directing groups, giving rise to good to excellent levels of remote asymmetric induction with OsO4–TMEDA. Interestingly, in all cases examined, trifluoroacetamides were found to be superior to trichloroacetamides as directing groups and an argument is presented which rationalises this observation.