1713-63-9Relevant academic research and scientific papers
Assembling contiguous quaternary carbon atoms: Regio- and stereoselective rearrangements in cobalt-directed radical reactions of 1,4-enynes
Melikyan, Gagik G.,Hughes, Rhoda,Rivas, Bianca,Duncan, Kellyanne,Sahakyan, Nare
, p. 242 - 253 (2015)
Radical coupling reactions of Co2(CO)6-complexed 1,4-enynes occur in a regio- and stereoselective fashion, providing access to 3E,7E-decadiene-1,9-diynes in excellent yields (84-99%). The formation of contiguous quaternary carbon ato
Rhodium-Catalyzed 1,1-Hydroacylation of Thioacyl Carbenes with Alkynyl Aldehydes and Subsequent Cyclization
Zhou, Bingnan,Wu, Qiuyue,Dong, Ziyang,Xu, Jiaxi,Yang, Zhanhui
, p. 3594 - 3599 (2019/05/24)
A rhodium-catalyzed 1,1-hydroacylation of thioacyl carbenes with alkynyl and alkenyl aldehydes and subsequent 6-endo-trig/dig cyclization are realized, giving structurally diverse 4H-thiopyran-4-ones and 2,3-dihydro-4H-thiopyran-4-ones in moderate to good yields. The oxidative addition of Rh(I) to aldehydes is proposed to be the turnover-limiting step. Manipulations of estrones demonstrate the applications of our formal (3 + 3) transannulations in the structural modifications of natural products.
Organoselenium-catalyzed, hydroxy-controlled regio- and stereoselective amination of terminal alkenes: Efficient synthesis of 3-amino allylic alcohols
Deng, Zhimin,Wei, Jialiang,Liao, Lihao,Huang, Haiyan,Zhao, Xiaodan
supporting information, p. 1834 - 1837 (2015/04/27)
An efficient route to prepare 3-amino allylic alcohols in excellent regio- and stereoselectivity in the presence of bases by orangoselenium catalysis has been developed. In the absence of bases α,β-unsaturated aldehydes were formed in up to 97% yield. Control experiments reveal that the hydroxy group is crucial for the direct amination.
Organocatalytic, Asymmetric Eliminative [4+2] Cycloaddition of Allylidene Malononitriles with Enals: Rapid Entry to Cyclohexadiene-Embedding Linear and Angular Polycycles
Brindani, Nicoletta,Rassu, Gloria,Dell'Amico, Luca,Zambrano, Vincenzo,Pinna, Luigi,Curti, Claudio,Sartori, Andrea,Battistini, Lucia,Casiraghi, Giovanni,Pelosi, Giorgio,Greco, Daniela,Zanardi, Franca
, p. 7386 - 7390 (2015/06/30)
A direct aminocatalytic synthesis has been developed for the chemo-, regio-, diastereo-, and enantioselective construction of densely substituted polycyclic carbaldehydes containing fused cyclohexadiene rings. The chemistry utilizes, for the first time, remotely enolizable π-extended allylidenemalononitriles as electron-rich 1,3-diene precursors in a direct eliminative [4+2] cycloaddition with both aromatic and aliphatic α,β-unsaturated aldehydes. The generality of the process is demonstrated by approaching 6,6-, 5,6-, 7,6-, 6,6,6-, and 6,5,6-fused ring systems, as well as biorelevant steroid-like 6,6,6,6,5- and 6,6,6,5,6-rings. A stepwise reaction mechanism for the key [4+2] addition is proposed as a domino bis-vinylogous Michael/Michael/retro-Michael reaction cascade. The utility of the malononitrile moiety as traceless activating group of the dicyano nucleophilic substrates is demonstrated.
Reduction of nitriles into aldehydes using a TMDS/V(O)(OiPr)3 reducing system
Laval, Stéphane,Dayoub, Wissam,Pehlivan, Leyla,Métay, Estelle,Delbrayelle, Dominique,Mignani, Gérard,Lemaire, Marc
, p. 23 - 26 (2014/01/06)
A simple and convenient method for the chemoselective reduction of nitriles into aldehydes using a 1,1,3,3-tetramethyldisiloxane (TMDS)/ triisopropoxyvanadium(V) oxide reducing system is described. Aromatic as well as aliphatic nitriles are reduced into the corresponding aldehydes in moderate to good yields.
A sandwich N-doped graphene/Co3O4 hybrid: An efficient catalyst for selective oxidation of olefins and alcohols
Nie, Renfeng,Shi, Juanjuan,Du, Weichen,Ning, Wensheng,Hou, Zhaoyin,Xiao, Feng-Shou
, p. 9037 - 9045 (2013/09/23)
A sandwich-like N-doped graphene/Co3O4 hybrid was prepared via a simple one-pot hydrothermal reaction in a solution of NH 3. Characterizations disclosed that highly dispersed Co 3O4 nanoparticles with dominant exposed {112} and {110} planes were fabricated on both sides of well-exfoliated N-doped graphene; N-dopants in the graphene matrix can prevent re-graphitization of graphene, strengthen the interaction between Co3O4 and the graphene matrix, and improve the dispersion of Co3O4. This hybrid (Co3O4/RGO-N) exhibited superior activity and stability for the epoxidation of styrene compared to bulk Co3O 4 and N-free graphene supported Co3O4. At the same time, the resulting catalyst also showed high compatibility with various olefins and alcohols with good conversion and high selectivity. This synergistic strategy can provide simple, efficient and versatile blue-prints for low-cost fabrication of graphene-based nanocomposites for extending applications where graphene has rarely been exploited and beyond.
Electrocyclization of oxatrienes in the construction of structurally complex pyranopyridones
Fotiadou, Anna D.,Zografos, Alexandros L.
supporting information, p. 5664 - 5667 (2013/01/15)
Application of a tandem Knoevenagel/6π-electrocyclization sequence is able to produce highly substituted pyranopyridones from moderate to high yields in a one-step reaction. High diasteroselectivity is observed in some cases and was rationalized on the basis of the thermodynamic control of the evidenced reversibility of a 6π-electrocyclization reaction. Numerous examples are provided establishing a novel entry in natural product-like structures of pyranopyridone alkaloids.
Lewis acid-catalyzed oxidative rearrangement of tertiary allylic alcohols mediated by TEMPO
Vatèle, Jean-Michel
experimental part, p. 904 - 912 (2010/03/24)
Two methods for the oxidative rearrangement of tertiary allylic alcohols have been developed. Most of tertiary allylic alcohols studied were oxidized to their corresponding transposed carbonyl derivatives in excellent to fair yields by reaction with TEMPO in combination with PhIO and Bi(OTf)3 or copper (II) chloride in the presence or not of oxygen. Other primary oxidants of TEMPO such as PhI(OAc)2, mCPBA, and Oxone were unsatisfactory giving the enone in modest to low yields.
Catalytic activity dependency on catalyst components in aerobic copper-TEMPO oxidation
Kumpulainen, Esa T. T.,Koskinen, Ari M. P.
experimental part, p. 10901 - 10911 (2010/04/05)
The influence of catalyst components in the copper-TEMPO (2,2,6,6-tetramethylpiperidine N-oxide) catalysed aerobic oxidation of alcohols was investigated. The type and amount of base greatly influences reactivity. The bipyridyl ligand concentration had no major influence on catalysis, but ex-cessive amounts led to a decrease in activity for longer reaction times. The kinetic dependency for TEMPO was found to be 1.15, and for copper 2.25, which is an indication of a binuclear catalytic system. Optimised conditions with various allylic and aliphatic alcohols give good to excellent rapid oxidations.
