RESUMEN
The synthesis of medicinally interesting aryldifluoromethylated compounds has drawn significant research attention in recent years. Herein, we report an unprecedented iron-mediated process for the selective defluorination of trifluoromethylarenes to achieve the 1,2-difluoroalkylthiolation of alkenes. Preliminary mechanistic studies revealed that thiolate anion, trifluoromethylarene, and iron cation could form an electron donor-acceptor (EDA) complex, which induced selective defluorination and then difunctionalization of alkenes to obtain aryldifluoromethylated products. The generated aryldifluoromethylated compounds make it difficult to form an EDA complex again, thus avoiding excessive defluorination. This conversion has concise and ambient reaction conditions and provides an alternative solution for obtaining difluorobenzylic intermediates.
RESUMEN
C-C σ-bond cleavage and reconstruction is a significant tool for structural modification in synthetic chemistry but it remains a formidable challenge to perform on unstrained skeletons. Herein, we describe a radical addition-enabled C-C σ-bond cleavage/reconstruction reaction of unstrained allyl ketones to access various functional indanones bearing a benzylic quaternary center. The synthetic utility of this method has been showcased by the first total synthesis of carexane L, an indanone-based natural product.
RESUMEN
Radical-mediated 1,2-difunctionalization of olefins is a well-established synthetic technique widely used in the rapid construction of structurally diverse molecular entities. However, radical-mediated 1,3-difunctionalization reactions are rare, and the substrates are generally limited to strained skeletons. Here, we report a practical approach for 1,3-difunctionalization of available ß,γ-unsaturated ketones via a radical cascade process including visible light-irradiated radical addition, thermodynamic stability-driven 1,2-carbonyl migration from unactivated all-carbon quaternary center, and terminal C-radical varied transformations. Various highly functionalized alkyl skeletons with different valuable functional groups at positions 1 and 3 and the carbonyl group at position 2 have been synthesized through a radical chain pathway or Cu-catalyzed Ritter-type reaction. Moreover, this protocol provides a real case of diversity-oriented radical rearrangement for drug discovery. We identified a previously unknown chemotype of dual inhibitors for hypoxia-inducible factor (HIF) and WNT signaling pathways from products. These small-molecule inhibitors could suppress HIF and WNT signaling-dependent HCT116 cell growth in 2D and 3D culture systems.