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Rate constants for hydrogen atom transfer reactions of the water, deuterium oxide, and methanol complexes of bis(cyclopentadienyl)titanium(III) chloride with secondary alkyl radical 1-cyclobutyldodecyl were reported. The rate constants were found to be about I order of magnitude smaller than those for radical reduction reactions of tin hydrides.

The ring opening kinetics of the 1-cyclobutyldodecyl radical was analyzed to determine the Arrhenius function over the temperature range -20 to 47 degree Celsius. The results showed that the ring opening of radical can be applied for calibration of slow radical reactions using 'radical clock' indirect kinetic methods.

The rate constants determined for reactions of triethylborane complexes of water and methanol as H-atom donors of alkyl radical were observed to be 2 orders of magnitude smaller than those for reactions of tin hydride reagents at room temperature.

The design and synthesis of gem-difluorinated sugar nucleosides are described. The key intermediate, 3-deoxy-3,3-difluoro-D-arabinofuranose 9, prepared from the chiral gem-difluorohomoallyl alcohol 12 is presented.

Kinetics of ring opening of the 1-cyclobutyldodecyl radical (1) were studied, and an Arrhenius function over the temperature range -20 to 47 °C was determined. The radical clock reaction has kinetics described by log k = 13.2 - 13.5/ 2.313RT (in kcal/mol), and k = 1.5 × l03 s~ at 20 °C. Previous kinetic studies of hydrogen atom transfer trapping of radical 1 by the triethylborane-methanol complex at variable temperatures (J. Org. Chem. 2007, 72, 5098) were analyzed with the newly obtained kinetic data. [ABSTRACT FROM AUTHOR]