Stereodivergent Nucleophilic Additions to Racemic β-Oxo Acid Derivatives: Fast Addition Outcompetes Stereoconvergence in the Archetypal Configurationally Unstable Electrophile
作者:Pedro De Jesús Cruz、Evan T. Crawford、Shubin Liu、Jeffrey S. Johnson
DOI:10.1021/jacs.1c07702
日期:2021.10.6
Additions of carbon nucleophiles to racemic α-stereogenic β-oxo acidderivatives that deliver enantiomerically enriched tertiary alcohols are valuable, but uncommon. This article describes stereodivergent Cu-catalyzed borylative cyclizations of racemic β-oxo acidderivatives bearing tethered pro-nucleophilic olefins to deliver highly functionalized cyclopentanols containing four contiguous stereogenic
将碳亲核试剂添加到外消旋 α-立体 β-氧代酸衍生物中,以提供对映异构体富集的叔醇是有价值的,但并不常见。本文描述了带有束缚前亲核烯烃的外消旋 β-氧代酸衍生物的立体发散 Cu 催化的硼化环化,以提供含有四个连续立体中心的高度官能化的环戊醇。报告的协议适用于一系列β-含氧酸衍生物,并且非对映体产物很容易通过典型的色谱技术分离。α-立体-β-酮酯通常被认为具有极端或自发的构型脆性,
Triazabicyclodecene as an Organocatalyst for the Regiospecific Synthesis of 1,4,5-Trisubstituted<i>N</i>-Vinyl-1,2,3-triazoles
作者:Dhevalapally B. Ramachary、Jagjeet Gujral、Swamy Peraka、G. Surendra Reddy
DOI:10.1002/ejoc.201601497
日期:2017.1.18
Herein we report on the 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) catalyzed enolate-mediated regiospecificsynthesis of 1,4,5-trisubstituted N-vinyl-1,2,3-triazoles from simple activated carbonyl compounds and N-vinyl azides through [3+2] cycloaddition; upon further hydrogenation, 1,4,5-trisubstituted N-alkyl-1,2,3-triazoles are furnished. Both the organo-click and hydrogenation reactions proceeded
required for this reaction. The synthetic utility is demonstrated by pinacol coupling of ketyl radicals and benzannulation of α-carbonyl radicals with alkynes to give a series of highly substituted 1-naphthols in good to excellent yields. The readily available photocatalyst, mild reaction conditions, broad substrate scope, and high functional-group tolerance make this reaction a useful synthetic tool
The electronic effects of tetranuclear zinc cluster catalysts on transesterification were investigated by changing the carboxylate ligands in the clusters. High catalyst activity crucially depended on the balance between Lewis acidity and Brønsted basicity of the catalyst; this was consistent with the dual activation of both the electrophile and nucleophile by the cooperative zinc centers. In addition