Scope and Mechanism of Formal S<sub>N</sub>2‘ Substitution Reactions of a Monomeric Imidozirconium Complex with Allylic Electrophiles
作者:Gojko Lalic、Jamin L. Krinsky、Robert G. Bergman
DOI:10.1021/ja7106096
日期:2008.4.1
bromides to give exclusively the products of the SN2' reaction; i.e., attack at the allylic position remote from the leaving group with migration of the doublebond. The primary amine products can be isolated in excellent yields, after in situ Cbz protection, in the presence of variety of functional groups. Good diastereoselectivity and complete stereoselectivity allowed the formation of enantioenriched
Zirconium-Mediated S<sub>N</sub>2‘ Substitution of Allylic Ethers: Regio- and Stereospecific Formation of Protected Allylic Amines
作者:Gojko Lalic、Suzanne A. Blum、Robert G. Bergman
DOI:10.1021/ja056132f
日期:2005.12.1
A new zirconium-mediated, regio- and stereospecific SN2' substitution of allylic ethers with a nitrogen nucleophile has been developed. Cbz-protected amine products were isolated in high yield from reactions with a wide range of Z allylic ethers. A mechanism of the allylic substitution consistent with the results of the kinetics and kinetic isotope effect studies was proposed.
已经开发出一种新的锆介导的、区域和立体特异性的 SN2' 取代烯丙醚与氮亲核试剂。从与各种 Z 烯丙基醚的反应中以高产率分离出 Cbz 保护的胺产物。提出了与动力学和动力学同位素效应研究结果一致的烯丙基取代机制。
Tandem Overman Rearrangement and Intramolecular Amidomercuration Reactions. Stereocontrolled Synthesis of <i>cis</i>- and <i>trans</i>-2,6-Dialkylpiperidines
作者:Om V. Singh、Hyunsoo Han
DOI:10.1021/ol048961w
日期:2004.9.1
[reaction: see text] Hg(II)-mediated tandem Overman rearrangement and intramolecular amidomercuration reactions were proven to provide a convenient tool for the stereoselective synthesis of cis- and trans-2,6-disubstituted piperidines. Thus, upon treatment with Hg(OTFA)(2) in THF, the trichloroacetimidate 1 directly transformed into the 2,6-dialkyl piperidine 2 with almost exclusive trans selectivity