Chemoselective protection of thiols versus alcohols and phenols. The Tosvinyl group
作者:Odón Arjona、Rocı́o Medel、Jenny Rojas、Anna M. Costa、Jaume Vilarrasa
DOI:10.1016/s0040-4039(03)01614-9
日期:2003.8
conjugate addition of aliphatic and aromatic thiols to ethynylp-tolylsulphone (tosylacetylene) has been managed to afford Tosvinyl derivatives chemoselectively (in the presence of oxygen nucleophiles) and stereoselectively (isomers Z) in practically quantitative yields. The conditions of choice are: catalytic amounts of Et3N (only 0.5–1.0 mol%), a reaction temperature around 0°C and, for the less acidic
Total Stereochemical Control in the Addition of Thiols to <i>p</i>-Toluenesulfonylacetylene. Synthesis of <i>Z</i>- and <i>E-</i>2-Sulfanylvinylsulfonyl Derivatives
作者:Rocío Medel、María I. Monterde、Joaquín Plumet、Jenny K. Rojas
DOI:10.1021/jo0402576
日期:2005.1.1
0 °C or rt without the use of any catalytic reagent to give good yields of Z-2-sulfanylvinylsulfonyl derivatives with total diastereoselectivity. On the other hand, in the presence of 1.1 equiv of NaH in THF, the same reaction affords the corresponding E-diastereomer also with total diastereoselectivity.