Tethered Aminohydroxylation (TA) Reaction of Amides
作者:Timothy J. Donohoe、Cedric K. A. Callens、Amber L. Thompson
DOI:10.1021/ol900631y
日期:2009.6.4
The first examples of amide-tethered aminohydroxylationreactions, catalyzed by osmium, showing that the use of N−O-based reoxidants are essential for success, are reported. The system that is described is compatible with a variety of different alkene substitution patterns and ring sizes and works with low loadings in both cyclic and acyclic systems. The levels of diastereoselectivity that were observed
catalytic activity with the suppression of catalyst deactivation. On the basis of a frontier molecular orbital (FMO) analysis, we systematically engineered a new catalyst system capable of a stepwise nitrenoid transfer to allow for nucleophile incorporation. Using the catalytic protocol, a range of difunctionalized lactams can be produced in a diastereoselective manner with various nucleophiles. Mechanistic
合成化学的中心主题之一是建立新的策略,以促进更有效和温和的反应的发展,并扩大不对称催化的化学空间。在此,我们提出了一种使 Cp*Ir(κ 2-LX) 系统作为通过氮烯介导的途径实现烯烃双官能化的催化剂。一个关键的策略是通过配体修饰来调整关键 Ir 氮烯中间体的轨道对称性,以通过抑制催化剂失活来赋予所需的催化活性。在前沿分子轨道 (FMO) 分析的基础上,我们系统地设计了一种新的催化剂体系,能够逐步进行氮烯转移,以允许亲核试剂的掺入。使用催化协议,可以使用各种亲核试剂以非对映选择性方式生产一系列双官能化内酰胺。机理研究表明,配体在类氮烯递送和立体选择性确定步骤中都起着至关重要的作用。
Enantioselective synthesis of 2,3-disubstituted piperidines from (S)-methylpyroglutamate
作者:Olivier Calvez、Angèle Chiaroni、Nicole Langlois
DOI:10.1016/s0040-4039(98)02190-x
日期:1998.12
N-methoxy-N-methylamide derived from (S)-methylpyroglutamate was prepared in good yield and allowed the addition of Grignard reagents. Erythro (2S)-1-benzyl-2-hydroxybenzyl pyrrolidine obtained by this way was converted into (2S,3R)-1-benzyl-3-hydroxy-2-phenylpiperidine and its chloro analog.
Enantioselective Henry Addition of Methyl 4-Nitrobutyrate to Aldehydes. Chiral Building Blocks for 2-Pyrrolidinones and Other Derivatives
作者:Gonzalo Blay、Víctor Hernández-Olmos、José R. Pedro
DOI:10.1021/ol1010888
日期:2010.7.2
enantioselective Henry addition of methyl 4-nitrobutyrate to aldehydes using a Cu(II)−amino pyridine complex as catalyst is described. The products resulting from this reaction constitute a new, highly versatile family of chiralbuildingblocks as a result of the presence of three different functional groups on the molecule. These products have been transformed into nonracemic chiral γ-lactams, 5-hydroxy-5-substituted