Cyclohydrocarbonylation of substituted alkynes and tandem cyclohydrocarbonylation–CO insertion of α-keto alkynes catalyzed by immobilized Co–Rh heterobimetallic nanoparticles
作者:Kang Hyun Park、So Yeon Kim、Young Keun Chung
DOI:10.1039/b416657d
日期:——
The use of cobaltârhodium (Co2Rh2) heterobimetallic nanoparticles in the cyclohydrocarbonylation of substituted alkynes and tandem cyclohydrocarbonylationâCO insertion of α-keto alkynes to give 2(3H)- or 2(5H)-furanones is described.
Palladium-Catalyzed Asymmetric Allylic Alkylation of Cyclic Dienol Carbonates: Efficient Route to Enantioenriched γ-Butenolides Bearing an All-Carbon α-Quaternary Stereogenic Center
Allyl dienol carbonates (1) served as substrates for the title reaction to afford the furanones 2 in both high yields and high enantioselectivities. These furanones were eventually converted into valuable buildingblocks including γ‐tertiary and γ‐quaternary furanones (3) as well as β‐quaternary butyrolactones (4). This method was used as a key step in the totalsynthesis of (−)‐nephrosteranic acid
Reactions of alkyl 4-hydroxybut-2-ynoates with arenes under superelectrophilic activation with triflic acid or HUSY zeolite: Alternative propargylation or allenylation of arenes, and synthesis of furan-2-ones
作者:Natalia A. Devleshova、Stanislav V. Lozovskiy、Aleksander V. Vasilyev
DOI:10.1016/j.tet.2019.130517
日期:2019.9
respectively. Reactions of these species with arenes at C4 lead to products of arene propargylation, alternatively, reactions at C2 result in allenylation of arenes, followed by further transformation into furan-2-ones. Using quantum chemical calculations by the DFT method, it has been shown that the reactivity of such propargyl-allenyl cations is mainly explained by orbital factors. Plausible reaction mechanism
烷基-4-芳基的反应(或4,4-二芳基)-4-羟基丁-2- ynoates [氩(H或Ar')(OH)C 4 -C 3 ≡C 2 -CO 2 ALK]与芳烃下三氟甲基磺酸TfOH或HUSY沸石的作用导致形成两种主要化合物:芳基取代的呋喃-2-酮或富电子芳烃的炔丙基化产物。在这些转换键的反应性中间体相应的起始butynoates中,Ar(H或Ar')(的O,O-双质子形式+ OH 2)C 4 -C 3 ≡C 2 - C(= O + H)(OAlk) ,其脱水会产生介晶的炔丙基-烯丙基阳离子Ar(H或Ar')(OH)4 C+ -C 3 ≡C 2 -C(= O + H)(OAlk)↔的Ar(H或Ar')(OH) 4 C = C 3 = 2 Ç + -C(= O + H)(OAlk),在碳C4和C2上分别具有两个亲电中心。这些物质与芳烃在C4的反应会导致芳烃的炔丙基化产物,或者,在C2的反应会
Tellurium in organic synthesis: synthesis of bioactive butenolides
作者:Bruno K. Bassora、Carlos E. Da Costa、Rogério A. Gariani、João V. Comasseto、Alcindo A. Dos Santos
DOI:10.1016/j.tetlet.2006.12.063
日期:2007.2
Reduction of (Z)-β-butyltelluro-enones gives the corresponding γ-hydroxy vinylic tellurides with retention of the double bond configuration. Reaction of γ-hydroxy vinylic tellurides with 2 equiv of n-butyllithium produces 1,4-C,O-dianions, which on reaction with carbon dioxide give the corresponding butenolides.
Chemo- and Regioselective Cyclohydrocarbonylation of α-Keto Alkynes Catalyzed by a Zwitterionic Rhodium Complex and Triphenyl Phosphite
作者:Bernard G. Van den Hoven、Bassam El Ali、Howard Alper
DOI:10.1021/jo000230w
日期:2000.6.1
alpha-Keto alkynes react with CO and H-2 in the presence of catalytic quantities of the zwitterionic rhodium complex (eta(6)-C6H5BPh3)Rh--(+)(1,5-COD) and triphenyl phosphite affording either the 2-, 2(3H)-, or 2(5H)-furanones in 61-93% yields. The cyclohydrocarbonylation is readily accomplished using substrates containing alkyl, aryl, vinyl, and alkoxy groups at the acetylenic terminal, as well as a variety of primary, secondary, and tertiary alkyl, aryl, and heteroaryl groups connected to the ketone functionality. Structural and electronic properties present in the starting materials mediate the chemo- and regioselectivity of the reaction.