Synthesis of the Branched C-Glycoside Substructure of Altromycin B
摘要:
[GRAPHICS]Tungsten-catalyzed cycloisomerization of alkynyl alcohols including 8 provides only the endocyclic enol ether (11) as a key intermediate for the branched C-glycoside substructure (2) of altromycin B. A sequence of Stille cross-coupling reaction and regio- and stereoselective functional group transformations affords each C13-diastereomer of the branched C-arylglycoside (2a and 2b).
Highly regioselective hydroiodination of terminal alkynes and silylalkynes with iodine and phosphorus reagents leading to internal iodoalkenes
摘要:
Markovnikov-type hydroiodination of terminal alkynes with iodine and Ph2P(O)H took place selectively to afford the corresponding internal iodoalkenes in good yields. Combination of (PhO)(2)P(O)H and Ph2P(O)OH instead of Ph2P(O)H also provided internal iodoalkenes in excellent yields. This hydroiodination is advantageous in terms of mild conditions, convenient operation, and tolerance to various functional groups. In addition, direct synthesis of internal iodoalkenes from silylalkynes was also achieved by using a mixed system of iodine and phosphorus reagents. (c) 2012 Elsevier Ltd. All rights reserved.
<i>N</i>-Iodosuccinimide-Initiated Spirocyclopropanation of Styrenes with 1,3-Dicarbonyl Compound for the Synthesis of Spirocyclopropanes
作者:Ping Qian、Bingnan Du、Ruichun Song、Xiaodong Wu、Haibo Mei、Jianlin Han、Yi Pan
DOI:10.1021/acs.joc.6b01163
日期:2016.8.5
Herein is reported an N-iodosuccinimide-initiated spirocyclopropanation reaction of styrenes with 1,3-dicarbonylcompounds in the presence of white LED light. The reaction proceeds via two C–H and two C–I bond cleavage event, along with two C–C bond formation event, and formation of quaternary centers. These reactions could be carried out at room temperature and tolerated a wide range of substrates
Inter- and intramolecular cycloaddition reactions of ethenetricarboxylates with styrenes and α-halostyrenes have been investigated. The reactions of ethenetricarboxylates with styrenes or α-bromostyrenes in the presence of SnCl4 or SnBr4 stereoselectively gave 2,4-cis-substituted cyclobutanes. The intramolecular cycloaddition reactions of a series of styrene-functionalized ethenetricarboxylate amides
Gold-Catalyzed Imination/Mannich Reaction Cascades of 3-En-1-ynamides with Anilines and Aldehydes to Enable 1,5-Nitrogen Functionalizations
作者:RahulKumar Rajmani Singh、Rai-Shung Liu
DOI:10.1002/adsc.201600072
日期:2016.4.28
Gold‐catalyzed imination/Mannich reaction cascades on readily available 3‐en‐1‐ynamides enable the diastereoselective synthesis of 1,5‐iminoamino compounds in a one‐pot operation. The reactions work well with diversified 3‐en‐1‐ynamides, aldehydes and anilines with good to excellent diastereoselectivities. Our control experiments indicate gold‐catalyzed aminations of 3‐en‐1‐ynamides to yield α‐imino
A Unique Ruthenium Carbyne Complex: A Highly Thermo-endurable Catalyst for Olefin Metathesis
作者:Mingbo Shao、Lu Zheng、Weixia Qiao、Jingjing Wang、Jianhui Wang
DOI:10.1002/adsc.201200119
日期:2012.10.8
A cationic rutheniumcarbynecomplex was prepared and was found to initiate olefinmetathesis reactions with good activities, which throws a new light on the design of a new type of rutheniumcatalyst for RCM reactions. More importantly, no double bond isomerized by-product was observed even at elevated temperatures in reactions catalyzed by the new carbynecomplex. A mechanism involving the in situ
Oxidative Addition of Alkenyl and Alkynyl Iodides to a Au
<sup>I</sup>
Complex
作者:Jamie A. Cadge、Hazel A. Sparkes、John F. Bower、Christopher A. Russell
DOI:10.1002/anie.202000473
日期:2020.4.16
intermolecular oxidative addition of alkenyl and alkynyl iodides to AuI are reported. Using a 5,5'-difluoro-2,2'-bipyridyl ligated complex, oxidative addition of geometrically defined alkenyl iodides occurs readily, reversibly and stereospecifically to give alkenyl-AuIII complexes. Conversely, reversible alkynyl iodide oxidative addition generates bimetallic complexes containing both AuIII and AuI centers. Stoichiometric