A Mild Synthesis of Vinyl Halides and gem-Dihalides Using Triphenyl Phosphite−Halogen-Based Reagents
摘要:
A new application of (PhO)(3)P-halogen-based reagents to the synthesis of vinyl halides and gem-dihalides is described. Vinyl halides were prepared in good to excellent yields from enolizable ketones, whereas aldehydes afforded the corresponding gem-dihalides. The halogenation proceeded smoothly under mild conditions.
A systematic study of the behaviour of aryl γ-halopropargyl ethers under thermal condition was undertaken. Aryl γ-bromopropargyl ethers underwent unique transformation in N,N-diethylanillne (215°C, 6 h) giving rise to a mixture of products ,and , whereas, under similar conditions aryl γ-chloropropargyl ethers ulbar|8, afforded 4-chlorochromenes, 9. A remarkable substituent and solvent effect has been
The regioselective intramolecularhydroarylation of (3‐halo‐2‐propynyl)anilines, (3‐halo‐2‐propynyl) aryl ethers, or (4‐halo‐3‐butynyl) aryl ethers was efficiently catalyzed by Rh2(OCOCF3)4 to give semihydrogenated aromatic heterocycles, such as 4‐halo‐1,2‐dihydroquinolines, 4‐halo‐3‐chromenes, or 4‐(halomethylene)chromans, in good to excellent yields. Some synthetic applications taking advantage of