644-30-4Relevant academic research and scientific papers
Transition-Metal-Free Valorization of Biomass-derived Levulinic Acid Derivatives: Synthesis of Curcumene and Xanthorrhizol
Fu, Yao,Gong, Tian-Jun,Xu, Wen-Yan,Zhuo, Kai-Feng
, p. 884 - 891 (2020/12/13)
Levulinic acid (LA) is acknowledged one of the most promising biomass-derived platform molecules and can be transformed into various value-added chemicals. Here, we report a new reaction process for the valorization of LA derivatives under transition-meta
Stereoselective Csp3?Csp2 Cross-Couplings of Chiral Secondary Alkylzinc Reagents with Alkenyl and Aryl Halides
Skotnitzki, Juri,Kremsmair, Alexander,Keefer, Daniel,Gong, Ye,de Vivie-Riedle, Regina,Knochel, Paul
, p. 320 - 324 (2019/11/26)
We report palladium-catalyzed cross-coupling reactions of chiral secondary non-stabilized dialkylzinc reagents, prepared from readily available chiral secondary alkyl iodides, with alkenyl and aryl halides. This method provides α-chiral alkenes and arenes with very high retention of configuration (dr up to 98:2) and satisfactory overall yields (up to 76 % for 3 reaction steps). The configurational stability of these chiral non-stabilized dialkylzinc reagents was determined and exceeded several hours at 25 °C. DFT calculations were performed to rationalize the stereoretention during the catalytic cycle. Furthermore, the cross-coupling reaction was applied in an efficient total synthesis of the sesquiterpenes (S)- and (R)-curcumene with control of the absolute stereochemistry.
Tandem Peterson olefination and chemoselective asymmetric hydrogenation of β-hydroxy silanes
Krajangsri, Suppachai,Wu, Haibo,Liu, Jianguo,Rabten, Wangchuk,Singh, Thishana,Andersson, Pher G.
, p. 3649 - 3653 (2019/03/28)
Here, we report the first Ir-N,P complex catalyzed tandem Peterson olefination and asymmetric hydrogenation of β-hydroxy silanes. This reaction resulted in the formation of chiral alkanes in high isolated yields (up to 99%) and excellent enantioselectivity (up to 99% ee) under mild conditions. Modification of the reaction conditions provides a choice to transform either an olefin or the β-hydroxy silane in a chemoselective manner. Additionally, based on this method, an expedient enantioselective synthesis of (S)-(+)-α-curcumene, from a simple ketone, was accomplished in two steps with 75% overall yield and 95% ee.
A asymmetric catalytic synthesis (S)- aryl curcumene method
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, (2017/08/25)
The invention discloses a method for asymmetrically catalyzing and synthesizing (S)-curcumene. According to the method, racemization 2-halogenated propionate ester serves as a starting material, under the catalysis of bis oxazoline/ cobalt, an asymmetrica
Stereospecific Hydrogenolysis of Lactones: Application to the Total Syntheses of (R)-ar-Himachalene and (R)-Curcumene
Spielmann, Kim,De Figueiredo, Renata Marcia,Campagne, Jean-Marc
, p. 4737 - 4743 (2017/05/12)
A straightforward strategy for the syntheses of curcumene and ar-himachalene is reported. Synthetic highlights include a catalytic and asymmetric vinylogous Mukaiyama reaction and a stereospecific hydrogenolysis of a tertiary benzylic center using Pd/C or Ni/Raney catalysts. Notably, using Ni/Raney, the stereoselectivity outcome (inversion vs retention) of the hydrogenolysis depends on the tertiary benzylic alcohol substitution.
Asymmetric synthesis of (R)-ar-curcumene, (R)-4,7-dimethyl-l-tetralone, and their enantiomers via cobalt-catalyzed asymmetric Kumada cross-coupling
Wu, Lin,Zhong, Jiang-Chun,Liu, Shi-Kuo,Liu, Fei-Peng,Gao, Zi-Dong,Wang, Min,Bian, Qing-Hua
, p. 78 - 83 (2015/12/31)
An efficient and concise asymmetric synthesis of (R)-(+)-ar-curcumene, (R)-4,7-dimethyl-l-tetralone, and their enantiomers was accomplished. The key step to construct the stereogenic benzylmethyl centers of these natural products is the cobalt-catalyzed a
A straightforward organocatalytic alkylation of 2-arylacetaldehydes: An approach towards bisabolanes
Gualandi, Andrea,Canestrari, Pietro,Emer, Enrico,Cozzi, Pier Giorgio
, p. 528 - 536 (2014/05/20)
A highly stereoselective organocatalytic aalkylation of 2-arylacetaldehydes with a commercially available carbenium tetrafluoroborate is described. The stereoselective alkylation was carried out in acetonitrile/ water, under air in the presence of a commercially available imidazolidinone (MacMillan's catalyst). Key intermediates for the synthesis of bisabolanes were obtained through a simple chemistry. In particular a direct, enantioselective and facile synthesis of (R)-(-)-curcumene is described.
Carboxy-directed asymmetric hydrogenation of α-alkyl-α-aryl terminal olefins: Highly enantioselective and chemoselective access to a chiral benzylmethyl center
Yang, Shuang,Zhu, Shou-Fei,Guo, Na,Song, Song,Zhou, Qi-Lin
supporting information, p. 2049 - 2052 (2014/03/21)
A carboxy-directed asymmetric hydrogenation of α-alkyl-α-aryl terminal olefins was developed by using a chiral spiro iridium catalyst, providing a highly efficient approach to the compounds with a chiral benzylmethyl center. The carboxy-directed hydrogenation prohibited the isomerization of the terminal olefins, and realized the chemoselective hydrogenation of various dienes. The concise enantioselective syntheses of (S)-curcudiol and (S)-curcumene were achieved by using this catalytic asymmetric hydrogenation as a key step.
Palladium/chiral amine co-catalyzed enantioselective β-arylation of α,β-unsaturated aldehydes
Ibrahem, Ismail,Ma, Guangning,Afewerki, Samson,C?rdova, Armando
, p. 878 - 882 (2013/02/23)
Palladium and a simple chiral amine are used as co-catalysts for the enantioselective conjugate addition of aryl boronic acids to α,β-unsaturated aldehydes (see scheme). The synthetic utility of this co-catalyzed reaction was demonstrated in the short tot
Pyrolytic formation of polycyclic aromatic hydrocarbons from sesquiterpenes
Francis, George W.,Christy, Alfred A.,Oygarden, Jostein
, p. 1316 - 1322 (2012/11/06)
The products of the pyrolysis of four sesquiterpenes, β-caryophyllene, α-cedrene, longifolene and valencene, have been examined. Pyrolysis was carried out at 300, 400 and 500 °C, the products determined by GC-MS and then examined for similarities and diff
