Epoxide-opening and group-transfer reactions mediated by monomeric zirconium imido complexes |
| |
Authors: | Blum Suzanne A Walsh Patrick J Bergman Robert G |
| |
Affiliation: | Center for New Directions in Organic Synthesis, Department of Chemistry, University of California, Berkeley, CA 94720, USA. |
| |
Abstract: | N-tert-Butylimidozirconocene (Cp2Zr=Nt-Bu) and its analogue (ebthi)Zr=NAr (ebthi = ethylenebis(tetrahydroindenyl), Ar = 2,6-dimethylphenyl) undergo overall cycloaddition reactions at ambient temperature with epoxides that lack accessible beta-hydrogens. The process results in addition of the Zr=N bond to an epoxide C-O bond, leading to azazirconacyclopentanes. The regio- and stereochemistry of the products implicate a stepwise mechanism, with the intermediacy of zwitterions having substantial carbocation character at the substituted carbon of the ring-opened epoxide-derived fragment. The azametallacycles undergo facile cleavage to beta-amino alcohols upon addition of mild acid. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|