Convenient and Highly Efficient Routes to 2
<i>H</i>
‐Chromene and 4‐Chromanone Derivatives: Iodine‐Promoted and
<i>p</i>
‐Toluenesulfonic Acid Catalyzed Cascade Cyclizations of Propynols
A convenient strategy is presented for the easy preparation of a series of 2H‐chromenes under mild conditions through iodocyclization of readily accessible propynols. In addition, various 4‐chromanones can be synthesized through a p‐toluenesulfonicacidcatalyzedcascadecyclization with high efficiency (yields up to 99 %). Our developed reaction systems are proven to have good functional‐group applicability
Synthesis of Substituted 1,2-Dihydropyridines from Propargyl Vinyl Ethers and Allenic Vinyl Ethers by Gold-Catalyzed Claisen Rearrangement and 6π-Aza-electrocyclization
作者:Hao Wei、Yao Wang、Bin Yue、Peng-Fei Xu
DOI:10.1002/adsc.201000292
日期:2010.10.4
An efficient synthetic method was developed for the construction of substituted 1,2-dihydropyridines by gold-catalyzed tandem reactions. The key intermediates 2,4-dienals were generated from propargyl vinyl ethers or allenic vinyl ethers with gold catalysts. These two reactions involved the process of gold-catalyzed [3,3]-sigmatropic rearrangement/isomerization/amine condensation/6π-aza-electrocyclization
Ruthenium Complex-Catalyzed Domino Addition/<i>exo</i>- Cycloisomerization of Propargylic Alcohols and Tosyl Isocyanate to Form Oxazolidinones
作者:Deng Yuan Li、Hao Jie Chen、Pei Nian Liu
DOI:10.1002/adsc.201401039
日期:2015.4.13
for dominoaddition/exo‐cycloisomerization of propargylic alcohols and tosyl isocyanate. In the presence of 2–5 mol% ruthenium complex, a range of terminal propargylic alcohols were reacted with tosyl isocyanate to furnish the corresponding oxazolidinone product exclusively in moderate to excellent yields. Mechanistic studies suggest that propargylic alcohol and tosyl isocyanate undergo addition firstly
An efficient method for the synthesis of (E)-1H-inden-1-ones using gold-catalyzed tandem [3,3]-propargyl esterrearrangement followed by Michael addition under mild reaction conditions has been developed. The resulting products are important frameworks found in numerous natural products and pharmaceutically active compounds, as well as being valuable intermediates in organic synthesis.
已开发了一种有效的方法,该方法使用金催化的串联[3,3]-炔丙基酯重排,然后在温和的反应条件下进行迈克尔加成,来合成(E)-1 H -inden-1-one。所得产物是在许多天然产物和药物活性化合物中发现的重要构架,并且是有机合成中的有价值的中间体。
Electrophilic Carbocyclization of Hydroxylated Enynes
Mild, efficient, and clean! Six‐membered cyclic products including diiodocyclohexadiene and 2,3‐diiodobenzene have been prepared in a iodonium‐induced internal carbocyclization of hydroxylatedenynes (see scheme). This reaction proceeds smoothly under mild reaction conditions, and all the halogen atoms (I and Br) generated from the electrophiles are used effectively.