A new two-stage regioselective access to nonsymmetric 3,5-diarylisoxazoles starting from readily available 2-aryl-1,1-dibromocyclopropanes is developed. The strategy based on the nitrosation/Suzuki arylation sequence ensures good yields of the products and a wide scope of substituents in both aryl rings. Using this strategy, a panel of combretastatin A-4 (CA-4) analogues presented by 3,5-diarylisoxazole structural motif was synthesized and evaluated for their biological activity[a] G.

A new convenient and versatile halogenating system (R 4 NHal/ NOHSO 4 ), giving straightforward and general access to halogenated 3,5diaryl-and alkylarylisoxazoles, pyrazoles and electron-rich benzenes from the corresponding scaffolds, is suggested. The method provides excellent regioselectivity, scalability to the gram scale, and a broad scope for both aromatics and halogens. A three-step, one-pot reaction protocol was developed, and a series of 3,5-diaryl-4-haloisoxazoles has been efficiently synthesized from 1,2-diarylcyclopropanes under suggested nitrosating− halogenating conditions.

No abstract

No abstract