The halogen-bonding interaction between I2 and N-iodosuccinimide (NIS) stabilized by a Lewis base (LB) has been explored. 1H NMR, nuclear Overhauser effect (NOE), and diffusion-ordered NMR spectroscopy (DOSY) suggest the generation of a 1:1:1 assembly, LB–I2–NIS. In contrast, when N-iodotrifluoromethanesulfonimide (INTf2) is used instead of NIS, LB–I5+–LB is generated. On the basis of these results
Copper-catalyzed enantioselective 1,2-borylation of 1,3-dienes
作者:Yangbin Liu、Daniele Fiorito、Clément Mazet
DOI:10.1039/c8sc01538d
日期:——
borylation of 2-substituted 1,3-dienes is reported. The use of a chiral phosphanamine ligand is essential in achieving high chemo-, regio-, diastereo- and enantioselectivity. It provides access to a variety of homoallylic boronates in consistently high yield and enantiomeric excess with 2-aryl and 2-heteroaryl 1,3-dienes as well as sterically demanding 2-alkyl 1,3-dienes. Preliminary investigations
Metal-Catalyst-Controlled Divergent Synthesis of γ-Butyrolactones via Intramolecular Coupling of Epoxides with Alcohols
作者:Feipeng Liu、Zifan Cheng、Yiyun Fang、Xuchao Wang、Lingzi Zhao、Zi-Qiang Rong
DOI:10.1021/acs.orglett.3c00898
日期:2023.5.26
A metal-controlled divergent protocol for the synthesis of α- and β-substituted γ-butyrolactones was developed through intramolecular coupling of epoxides with alcohols. This method provides an efficient and practicable way to afford γ-butyrolactones with good efficiency, excellent regioselectivity, and broad substrate scope.
The reductive opening of oxetanes by CP2TiCl was investigated by a combined synthetic and computational study. The activation and reaction energies predict a more difficult reaction than the related epoxide opening. Synthetically, the gamma-titanoxy radicals obtained behave like typical free radicals. Their reactions are not controlled by the metal and its ligands. This is highlighted by the dimerization of phenyl substituted oxetane derived radicals. (C) 2008 Elsevier Ltd. All rights reserved.
Enantioselective Small Molecule Synthesis by Carbon Dioxide Fixation using a Dual Brønsted Acid/Base Organocatalyst
作者:Brandon A. Vara、Thomas J. Struble、Weiwei Wang、Mark C. Dobish、Jeffrey N. Johnston
DOI:10.1021/jacs.5b04425
日期:2015.6.17
Carbon, dioxide exhibits many of the qualities of an ideal reagent: it is nontoxic, plentiful, and inexpensive. Unlike other gaseous reagents, however, it has found limited use in enantioselective synthesis. Moreover, unprecedented is a tool that merges one of the Simplest biological :approaches to catalysis-Bronsted acid/base activation with this abundant reagent. We describe a metal-free small molecule catalyst that achieves the three component reaction between a homoallylic alcohol, carbon dioxide, and an electrophilic Source of iodine. Cyclic carbonates are formed enantioselectively.