Palladium catalyzed couplings of enol triflates with alkynes under very mild conditions - the stereoselective synthesis of dienediynes from bis(enoltriflates)

Application of Sonogashira and Baylis–Hillman Reactions with β-Trifluoromethylated Acroleins

The reaction of alkynes with 2-phenyl-3-iodo-4,4,4-trifluorobut-2-enal in the presence of palladium (0) is reported (Sonogashira reaction). Moreover, 2-(hydroxytrifluoromethylalkenyl)cyclohexenones have been prepared by the reaction of cyclohexenone and β-trifluromethylacroleins in the presence of N-methylimidazole catalysis.

Novel designed enediynes: molecular design, chemical synthesis, mode of cycloaromatization and guanine-specific DNA cleavage

The molecular design and chemical synthesis of novel enediyne molecules related to the neocarzinostatin chromophore (1), and their chemical and DNA cleaving properties are described. The 10-membered enediyne triols 16-18 were effectively synthesized from xylitol (10) in a short step, and found to be quite stable when handled at room temperature. The representative and acylated enediyne 16 was cycloaromatized by 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in cyclohexa-1,4-diene-benzene to give the benzenoid product 21 through a radical pathway. On the other hand, the enediyne 16 was cycloaromatized by diethylamine in dimethyl sulfoxide-Tris-HCl, pH 8.5 buffer to afford another benzenoid product 22 as a diethylamine adduct through a polar pathway. Furthermore, the enediynes 16-18 were found to exhibit guanine-specific DNA cleavage under weakly basic conditions with no additive.