RESUMEN
A practical and efficient solvent-free synthesis of ß-trifluoromethyl-substituted phosphonates and phosphine oxides via hydrophosphonylation and hydrophosphinylation of α-(trifluoromethyl)styrenes with H-phosphonates and H-phosphine oxides, respectively, was developed. The reaction proceeded smoothly within 2 h at room temperature without the cleavage of the rather fragile C-F bond in α-(trifluoromethyl)styrenes and afforded a wide variety of structurally diverse and valuable ß-trifluoromethyl-containing phosphonates and phosphine oxides in moderate to good yields. This protocol features mild conditions, wide substrate scope, simple manipulation, and excellent functional group compatibility.
RESUMEN
A mild and practical Fe-catalyzed hydroxytrifluoromethylation of α-(trifluoromethyl)styrenes with CF3SO2Na in the presence of K2S2O8 and air was developed. The reaction proceeded efficiently at room temperature without ß-fluoride elimination and afforded the corresponding α,ß-bistrifluoromethyl tertiary alcohols in good to excellent yields.
Asunto(s)
EstirenosRESUMEN
Two attractive chirons, aldehyde 6 and chloride 7, exhibiting functionalized ent-spongiane-type tricyclic skeletons (ABC ring system), have been constructed and their absolute configurations have been studied by NMR spectroscopy and confirmed by single-crystal X-ray diffraction. Both of these chirons are derived from commercially available andrographolide in good yield. Aldehyde 6 is obtained through a novel K2 S2 O8 -catalyzed aquatic ring-closing reaction of allylic sodium sulfonate and intramolecular 1,7-hydrogen atom transfer process. Further mechanistic investigations demonstrate that the 1,7-hydrogen atom transfer is a free-radical process, whereby hydrogen migrates from C18 to C17, as evidenced by double-18- deuterium-labeled isotope experiments. Prospective applications of these two chiral sources are also discussed.
RESUMEN
A mild and efficient DBN-mediated addition reaction of α-(trifluoromethyl)styrenes with diazoles, triazoles, tetrazoles, and primary, secondary, and secondary cyclic amines was developed. This practical protocol provided a robust method for the synthesis of various ß-trifluoromethyl nitrogen-containing heterocycles and ß-trifluoromethyl amines.
Asunto(s)
Estirenos , Triazoles , Aminas , TetrazolesRESUMEN
Four unprecedented base-catalyzed/mediated nucleophilic additions of TMSCN to α-(trifluoromethyl)styrenes and 2-trifluoromethyl enynes were developed. The reaction proceeded smoothly at room temperature under mild and transition-metal-free conditions without affecting the trifluoromethyl group and afforded the corresponding CF3-containing alkyl, alkynyl, and butadienyl nitriles in moderate to excellent yields in a highly regioselective manner, respectively.