Selective Synthesis of 5- or 6-Aryl Octahydrocyclopenta[b]pyrroles from a Common Precursor through Control of Competing Pathways in a Pd-Catalyzed Reaction
摘要:
The Pd/phosphine-catalyzed reaction of 1 with aryl bromides leads to the selective synthesis of either 6-aryl octahydrocyclopenta[b]pyrroles (3), the corresponding 5-aryl isomers 5, diarylamine 2, or hexahydrocyclopenta[b]pyrrole 4 depending on the structure of the phosphine ligand. These transformations are effective with a variety of different aryl bromides and provide 3-5 with excellent levels of diastereo-selectivity (dr >= 20:1). The changes in product distribution are believed to derive from the influence of Pd-catalyst structure on the relative rates of reductive elimination, beta-hydride elimination, alkene insertion, and alkene displacement processes in a mechanistically complex reaction. The effect of phosphine ligand structure on product distribution is described in detail, along with analysis of a proposed mechanism for these transformations.
Iodine(V) Reagents in Organic Synthesis. Part 1. Synthesis of Polycyclic Heterocycles via Dess−Martin Periodinane-Mediated Cascade Cyclization: Generality, Scope, and Mechanism of the Reaction
作者:K. C. Nicolaou、P. S. Baran、Y.-L. Zhong、K. Sugita
DOI:10.1021/ja012124x
日期:2002.3.1
reaction of unsaturated anilides discovered during the total synthesis of the CP-molecules (phomoidrides A and B) are delineated. A plethora of heterocyclic compounds are accessible by employing gamma,delta-unsaturated amides (derived fromanilines and carboxylic acids), urethanes, or ureas (derived from isocyanates and allylic alcohols and amines) as substrates. Optimization of the reaction led to room-temperature
描述了在 CP 分子(phomoidrides A 和 B)的全合成过程中发现的不饱和苯胺的 Dess-Martin periodinane 介导的环化反应的范围、一般性和机制。通过使用γ,δ-不饱和酰胺(衍生自苯胺和羧酸)、氨基甲酸酯或脲(衍生自异氰酸酯和烯丙醇和胺)作为底物,可以获得大量杂环化合物。反应的优化导致室温条件,而同位素标记研究为这种级联反应提供了机械原理。
Photoredox-catalyzed aminofluorosulfonylation of unactivated olefins
motifs in many areas, among which the emerging sulfur(VI) fluoride exchange (SuFEx) click chemistry is the most prominent. Here, we report the first three-component aminofluorosulfonylation of unactivatedolefins by merging photoredox-catalyzed proton-coupled electron transfer (PCET) activation with radical relay processes. Various aliphatic sulfonyl fluorides featuring a privileged 5-membered heterocyclic
Selective Synthesis of 5- or 6-Aryl Octahydrocyclopenta[<i>b</i>]pyrroles from a Common Precursor through Control of Competing Pathways in a Pd-Catalyzed Reaction
作者:Joshua E. Ney、John P. Wolfe
DOI:10.1021/ja0430346
日期:2005.6.1
The Pd/phosphine-catalyzed reaction of 1 with aryl bromides leads to the selective synthesis of either 6-aryl octahydrocyclopenta[b]pyrroles (3), the corresponding 5-aryl isomers 5, diarylamine 2, or hexahydrocyclopenta[b]pyrrole 4 depending on the structure of the phosphine ligand. These transformations are effective with a variety of different aryl bromides and provide 3-5 with excellent levels of diastereo-selectivity (dr >= 20:1). The changes in product distribution are believed to derive from the influence of Pd-catalyst structure on the relative rates of reductive elimination, beta-hydride elimination, alkene insertion, and alkene displacement processes in a mechanistically complex reaction. The effect of phosphine ligand structure on product distribution is described in detail, along with analysis of a proposed mechanism for these transformations.