A regioselective radical hydroboration of -difluoroalkenes was developed for the synthesis of α-difluoroalkylborons. The reaction features excellent regioselectivity, broad substrate scope, and good functional group capability. DFT calculations implicated the remarkable α-selectivity was driven from the kinetically and thermodynamically more favorable α-addition step. The resulting α-difluoroalkylborons could be readily converted into NHC-borane-tethered monofluoroalkenes, which demonstrated unique reactivity and applicability in the synthesis of monofluoroalkene derivatives through transformations of the boron unit.
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http://dx.doi.org/10.1021/acs.orglett.9b03173 | DOI Listing |
JACS Au
December 2024
State Key Laboratory of Fine Chemicals, School of Chemistry, Dalian University of Technology, Dalian 116024, China.
Nitroaromatics, as an important member and source of nitrogen-containing aromatics, is bringing enormous economic benefits in fields of pharmaceuticals, dyes, pesticides, functional materials, fertilizers, and explosives. Nonetheless, the notoriously polluting nitration industry, which suffers from excessive discharge of fumes and waste acids, poor functional group tolerance, and tremendous purification difficulty, renders mild, efficient, and environmentally friendly nitration a formidable challenge. Herein, we develop a visible-light-driven biocompatible arene C-H nitration strategy with good efficiency and regioselectivity, marvelous substrate applicability and functional group tolerance, and wide application in scale-up synthesis, total synthesis, and late-stage functionalization.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, China.
Here, we report the enantioselective total syntheses of four diepoxy--kaurane diterpenoids including (-)-Macrocalin B, (-)-Acetyl-macrocalin B, and (-)-Isoadenolin A and the revised structure of (-)-Phyllostacin I, which hinges on the strategic design of a regioselective and stereospecific trapping of a highly reactive [3.2.1]-bridgehead enone intermediate via a tethered intramolecular Diels-Alder reaction.
View Article and Find Full Text PDFJ Org Chem
December 2024
College of Biological, Chemical Sciences and Engineering, Jiaxing University, Jiaxing 314001, Zhejiang, China.
In this work, a switchable synthesis of β-ketosulfone and α-chloroketone through a radical difunctionalization of alkenes is reported. The transformation works well under iron peroxo species/photoredox dual catalysis and an open-flask atmosphere, and the reaction is highlighted with good yields and a broad reaction scope. Mechanism studies show that the reaction is initiated by a formal [4 + 2] cyclization of the sulfonyl radical in a regioselective manner.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Jinan University College of Pharmacy, College of Pharmacy, CHINA.
Highly functionalized xanthenes possess an impressive range of bioactivities and daunting synthetic challenge due to their unique ring systems and stereocenters. Here, we report an unprecedented ketyl radicals-induced skeletal rearrangement reaction of spirodihydrobenzofurans, enabled by zero-valent iron as reducing agents via photoredox catalysis, facilitating the facile preparation of various highly functionalized xanthenes. The features of this protocol include high chemo- and regioselectivity, exceptionally mild conditions, a broad substrate scope, scalability to gram-scale quantities, and consistent delivery of good to excellent yields.
View Article and Find Full Text PDFJ Org Chem
December 2024
College of New Energy, State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580, P. R. China.
The photocatalytic dearomative 1,4-hydroboration of naphthalenes with an N-heterocyclic carbene borane (NHC-BH) complex was reported herein with controllable regioselectivity and chemoselectivity. This protocol yielded a wide range of naphthalene derivatives bearing various functional groups, notably bioactive compounds. Hydroboration occurred through the cooperation of photoredox and hydrogen atom transfer via boryl radical addition to naphthalene and further selective protonation.
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