RESUMO
As novel difluoromethyl building blocks, difluoromethylated N-acylhydrazones react with allyltrimethylsilanes and the halogen source via a tandem addition/cyclization/halogenation strategy, which produces various difluoromethylpyrazoline compounds in good yields. The method features mild reaction conditions, broad substrate scopes, and a transition metal-free process with easy operation. It also proves that difluoromethylated N-acylhydrazones are useful difluoromethyl building blocks for the construction of difluoromethylated nitrogen heterocycles.
RESUMO
A visible-light-induced four-component Ritter-type reaction was developed for the synthesis of ß-trifluoromethyl imides from CF3Br, alkenes, carboxylic acids, and nitriles. This protocol features mild reaction conditions, a broad substrate scope, and excellent functional group compatibility. Furthermore, this method has been proven to be suitable for the late-stage diversification of drug molecules. A mechanism involving a Ritter-type reaction and Mumm rearrangement was proposed on the basis of the control experiments.
Assuntos
Imidas , Luz , Imidas/química , Alcenos/química , Ácidos Carboxílicos/química , Nitrilas/químicaRESUMO
Efficient visible-light-induced radical cascade trifluoromethylation/cyclization of inactivated alkenes with CF3Br, which is a nonhygroscopic, noncorrosive, cheap and industrially abundant chemical, was developed in this work, producing trifluoromethyl polycyclic quinazolinones, benzimidazoles and indoles under mild reaction conditions. The method features wide functional group compatibility and a broad substrate scope, offering a facile strategy to pharmaceutically produce valuable CF3-containing polycyclic aza-heterocycles.
Assuntos
Benzimidazóis , Indóis , Quinazolinonas , Catálise , LuzRESUMO
An efficient and novel photoinduced trifluoromethylation employing CF3Br as a trifluoromethyl source is described. With commercially accessible fac-Ir(III)(ppy)3 as the catalyst, radical trifluoromethylation between O-silyl enol ether and CF3Br occurs successfully. This method provides various α-CF3-substituted ketones with a broad substrate scope in good yields under mild reaction conditions.
RESUMO
A new strategy for the synthesis of chiral α-amino phosphonates by enantioselective C-H phosphonylation of allylamine with phosphite in the presence of a chiral Brønsted acid catalyst has been developed. This protocol successfully integrates direct C-H oxidation with asymmetric phosphonylation and exhibits high enantioselectivity.
RESUMO
The first Cu-catalyzed cascade sp(3) C-H bond oxidative functionalization of the 2-ethylazaarenes has been developed. The two different sp(3) C-H bonds in 2-ethylazaarenes are selectively oxidized and four new types of bonds (C=O, C=N, C-C, C-O) are constructed in one operation. Starting from the simple substrates and cheap nitro source, this reaction provides an efficient approach to produce new kinds of isoxazolines.