Radical, One-Step Approach to <i>o</i>-Chlorophenyl Thioethers from Xanthates. A Rapid Access to Vinylsilanes
作者:Matthieu Corbet、Zorana Ferjančić、Béatrice Quiclet-Sire、Samir Z. Zard
DOI:10.1021/ol801348u
日期:2008.8.21
Xanthates have been readily converted into o-chlorophenyl thioethers using a one-step procedure conducted under radical conditions. In some selected cases, these aryl thioethers were successfully oxidized to the corresponding sulfoxides and sulfenic acid elimination afforded the corresponding vinylsilanes.
Is an Iodine Atom Almighty as a Leaving Group for Bu<sub>3</sub>SnH-Mediated Radical Cyclization? The Effect of a Halogen Atom on the 5-Endo-trig Radical Cyclization of <i>N</i>-Vinyl-α-halo Amides
The effect of a halogen atom as a leaving group on Bu3SnH-mediated 5-endo-trig radical cyclization of N-(cyclohex-l-enyl) alpha-halo amides was examined. The cyclization of alpha-chloro amides occurred with a high degree of efficiency, whereas the corresponding alpha-iodo congeners gave only limited quantities of cyclization products. A detailed study revealed that these phenomena could be attributed to the initial conformations of alpha-halo amides. The cyclizing ability of alpha-iodo amides can be restored with Bu3SnCl or Bu3SnF as an additive. The cyclization of an alpha-iodo amide in the presence of Bu3SnF could be applied to a short-step synthesis of lycoranes featuring sequential 5-endo-trig and 6-endo-trig radical cyclizations.