Ligand-Enabled Monoselective β-C(sp<sup>3</sup>)–H Acyloxylation of Free Carboxylic Acids Using a Practical Oxidant
作者:Zhe Zhuang、Alastair N. Herron、Zhoulong Fan、Jin-Quan Yu
DOI:10.1021/jacs.0c01214
日期:2020.4.8
recent disclosure of the β-lactonization of free aliphatic acids, the use of peroxides in C-H activation reactions directed by weakly coordinating native functional groups was unreported. Herein we report C(sp3)-H β-acetoxylation and γ-, δ-, and ε-lactonization reactions of freecarboxylicacids enabled by a novel cyclopentane-based mono-N-protected β-amino acid (MPAA) ligand. Notably, tert-butyl hydrogen
[EN] LIGAND-ENABLED ß-C(sp3)–H LACTONIZATION FOR ß-C–H FUNCTIONALIZATIONS<br/>[FR] LACTONISATION DE SS-C(SP3)–H PERMISE PAR UN LIGAND POUR FONCTIONNALISATIONS SS-C–H
申请人:SCRIPPS RESEARCH INST
公开号:WO2020243754A1
公开(公告)日:2020-12-03
Provided herein is a method of forming a beta-lactone from a carboxylic acid having a beta-carbon with a hydrogen atom disposed thereon. The method comprises contacting a carboxylic acid of formula (1) as described herein with an effective amount of a palladium(II) catalyst, an effective amount of an N-protected aminoacid ligand, and t-butylhydroperoxide in a solvent comprising hexafluoroisopropanol (HFIP), at about 60˚C to provide a beta-lactone of formula (2) as described herein.
Visible-Light-Induced C–O Bond Formation for the Construction of Five- and Six-Membered Cyclic Ethers and Lactones
作者:Honggu Im、Dahye Kang、Soyeon Choi、Sanghoon Shin、Sungwoo Hong
DOI:10.1021/acs.orglett.8b03166
日期:2018.12.7
Visible-light-induced intramolecular C–O bond formation was developed using 2,4,6-triphenylpyrylium tetrafluoroborate (TPT), which allows the regiocontrolled construction of cyclic ethers and lactones. The reaction is likely to proceed through the single-electron oxidation of the phenyl group, followed by the formation of a benzylic radical, thus preventing a competing 1,5-hydrogen abstraction pathway
Nickel(0)/NaHMDS adduct-mediated intramolecular alkylation of unactivated arenes via a homolytic aromatic substitution mechanism
作者:Louis-Philippe B. Beaulieu、Daniela Sustac Roman、Frédéric Vallée、André B. Charette
DOI:10.1039/c2cc33547f
日期:——
A variety of polycycles can be synthesized via an intramolecular alkylation cyclization promoted by Ni(PPh3)4 and NaHMDS. Mechanistic investigations support the catalytic nature of Ni0 in the course of TEMPO scavenging experiments and its association with the substrate and NaHMDS to form an adduct by DOSY NMR.
Lactonization as a general route to β-C(sp3)–H functionalization
作者:Zhe Zhuang、Jin-Quan Yu
DOI:10.1038/s41586-019-1859-y
日期:2020.1.30
free aliphatic acids without exogenous directing groups. Considering the challenge of developing C–H activation reactions, it is not surprising that achieving different transformations requires independent catalyst design and directing group optimizations in each case. Here we report a Pd-catalysed β-C(sp3)–H lactonization of aliphatic acidsenabled by a mono-N-protected β-amino acid ligand. The highly