Reactions of Unsaturated Azides; Part 17:An Efficient Strategy for the Synthesis of Small-Ring Heterocycles via Isomerization of 2-Halo-2<i>H</i>-azirines
作者:Klaus Banert、Joseph Rodolph Fotsing
DOI:10.1055/s-2005-918513
日期:——
New acceptor-substituted allenyl halides were synthesized. The addition of hydrazoic acid (HN3) to these allenyl halides led to the formation of new 1-azido-2-haloethene derivatives. The photolysis of the latter compounds afforded the corresponding 2-halo-2H-azirines. At room temperature or below, they isomerized irreversibly by [1,2]-rearrangement of halogen to form other azirine isomers in very good yields. It is the first time that such a complete rearrangement of 2-halo-2H-azirines is observed. This synthetic strategy offers the possibility to observe both azirine isomers in their pure forms from single 1-azido-2-haloethene precursor.
The [2,3]-sigmatropic rearrangement of propargyl benzenesulphinates to allenyl phenyl sulphones
作者:S. Braverman、H. Mechoulam
DOI:10.1016/s0040-4020(01)97078-4
日期:1974.1
undergo thermalrearrangement in high yields to sulphones, accompanied by a simultaneous acetylene-allene isomerization. The allenic sulphones produced by the rearrangement of the α-monosubstituted propargyl esters underwent further rearrangement under the reaction conditions, to γ-substituted propargyl phenyl sulphones, by way of a base-catalyzed [1,3] - prototropic shift. A kinetic study of the rearrangement
Described here is the R3P/ICH2CH2I-promoted dehydroxylativesulfonylation of alcohols with a variety of sulfinates. In contrast to previous dehydroxylativesulfonylation methods, which are usually limited to active alcohols, such as benzyl, allyl, and propargyl alcohols, our protocol can be extended to both active and inactive alcohols (alkyl alcohols). Various sulfonyl groups can be incorporated,
此处描述的是 R 3 P/ICH 2 CH 2 I 促进的醇与各种亚磺酸盐的脱羟基磺酰化反应。与以前的脱羟基磺酰化方法通常仅限于活性醇(如苯甲基醇、烯丙基醇和炔丙醇)相比,我们的方案可以扩展到活性醇和非活性醇(烷基醇)。可以并入各种磺酰基,例如CF 3 SO 2和HCF 2 SO 2,它们是药物化学中感兴趣的氟化基团,其安装受到越来越多的关注。值得注意的是,所有试剂都很便宜且广泛可用,并且在 15 分钟的反应时间内获得了中等到高产率。
Synthesis and Biological Activities of Aryl Propargyl Sulfone
AbstractA series of molecules containing monopropargyl sulfone or 1, 2‐bis‐propargyl sulfone were synthesized. The cytotoxicity of these compounds against human carcinoma cells was also examined. This study indicated that the formation of a biradical intermediate is important to the potency of cytotoxicity.
Reduction of propargylic sulfones to (Z)-allylic sulfones using zinc and ammonium chloride
作者:Helen M. Sheldrake、Timothy W. Wallace
DOI:10.1016/j.tetlet.2007.04.099
日期:2007.6
Propargylic sulfones can be cis-hydrogenated using commercial zinc powder and ammonium chloride in THF-water at room temperature, the major products being the corresponding (Z)-allylic sulfones. Other reducible groups (alkene, benzyloxy) are not affected. Allenylsulfones are implicated in one of the possible reaction pathways. (c) 2007 Elsevier Ltd. All rights reserved.