Search

An efficient BF3·OEt2-mediated propargyl alcohol rearrangement/[1,5]-hydride transfer/cyclization cascade for the synthesis of tetrahydroquinoline derivatives has been described. The substituents adjacent to triple bonds play an important role in the formation of ketones (via [1,3]-hydroxyl shift) or alkenyl fluorides which are products of formal trans-carbofluorination of internal alkynes. This method provides a rapid access to diverse heterocycles in moderate to excellent yields.

A novel and efficient protocol for desulfonylation-initiated distal alkenyl migration and its application to the elusive alkenylation of unactivated alkenes have been presented. This radical cascade process has successfully achieved the vicinal difluoroalkylalkenylation of unactivated alkenes with excellent chemo-, regio-, and stereoselectivity in high efficiency under mild conditions. The reactions afford previously unknown 3,3-difluoro-5-styrylpiperidin-2-one derivatives or β-styryl-γ-difluoroalkyl amines bearing a quaternary stereocenter. This is the first report of difunctionalization of unactivated alkenes through desulfonylation-initiated distal alkenyl migration.

A novel and practical Cu-catalyzed aerobic oxidative synthesis of thiazoles was developed. This chemistry for the first time achieved thiazole construction from simple aldehydes, amines, and element sulfur through multiple Csp3–H bond cleavage processes. Molecular oxygen was used as a green oxidant in this oxidative protocol. The substrate scope is broad with the tolerance of aliphatic amines. The mechanistic study might promote the reaction design for a new sulfuration/annulation reaction with readily available element sulfur.

An efficient BF

A novel and efficient rhodium- and copper-co-catalyzed C-H bond activation and annulation for the construction of bioactively important quinazolines has been developed. This [4 + 2] annulation strategy utilizing alkyl azides as the carbon-heteroatom synthons shows high efficiency in the synthesis of six-membered benzoheterocycles containing two heteroatoms. This aerobic oxidative protocol provides a useful application of simple alkyl azides in N-heterocycle synthesis with N2 and H2O as byproducts.

A novel and practical Cu-catalyzed aerobic oxidative synthesis of thiazoles was developed. This chemistry for the first time achieved thiazole construction from simple aldehydes, amines, and element sulfur through multiple Csp

The catalytic decarboxylative nitrogenation of aliphatic carboxylic acids for the synthesis of alkyl azides is reported. A series of tertiary, secondary, and primary organoazides were prepared from easily available aliphatic carboxylic acids by using K2S2O8 as the oxidant and PhSO2N3 as the nitrogen source. The EPR experiment sufficiently proved that an alkyl radical process was generated in the process, and DFT calculations further supported the SET process followed by a stepwise SH2 reaction to afford azide product.

A highly selective copper-catalyzed concise synthesis of 3,5-diarylpyridine and 2-(1H)-pyridone has been achieved through cascade Chichibabin-type cyclization, C(sp(3))-C(sp(3)) cleavage, and aerobic oxidation. Azide, ceric ammonium nitrate (CAN), and 2-aminopyridine are disclosed as efficient nitrogen donors in this Cu-catalysis using O2 as the oxidant. Water and molecular oxygen were employed as the oxygen source in the case of oxygenation.

A mild and efficient protocol for photoredox-catalyzed azidofluoroalkylation of simple alkenes is described with readily available fluoroalkyl iodides. This method allows for a direct and regioselective formation of C–RF and C–N3 bonds from the C═C moiety. A variety of fluoroalkyl groups including the CF3 group can be selectively introduced to olefins to afford a series of β-fluoroalkylated azides.

A general and facile synthetic method for C(sp2)–H difluoroalkylations and perfluoroalkylations of alkenes and (hetero)arenes with commercially available fluoroalkyl halides has been developed with a copper-amine catalyst system. This method is characterized by high yields, mild reaction conditions, low-cost catalyst, broad substrate scope, and excellent functional group compatibility, therefore providing a convenient synthetic strategy toward various difluoroalkyl- and perfluoroalkyl-substituted alkenes and (hetero)arenes.