- Scalable Total Synthesis of (+)- And (-)-Codonopiloneolignanin A via Ti(IV)/NHC Cooperative Control Highly Enantioselective Dimerization of Multisubstituted Cinnamaldehyde
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The first gram-scale asymmetric total synthesis of (+)- and (-)-codonopiloneolignanin A has been achieved from multisubstituted cinnamaldehyde in four steps with 37% overall yield. The synthetically challenging tricyclic [5, 3, 0, 03,8] decane skeleton was efficiently constructed via a highly enantioselective dimerization of multisubstituted cinnamaldehyde, followed by a sequence of cascade reactions including Prins cyclization, cation mediated cyclization, and deprotection. Furthermore, the scope of NHC-catalyzed/Ti(IV)-mediated synergistic control multisubstituted cinnamaldehyde dimerization was investigated. Significantly, the bioactivity of codonopiloneolignanin A and its enantiomer, particularly scarce in nature, was tested and showed good anticancer activity.
- Li, Xiangxin,Yong, Huaya,Fan, Xiaohong,Zheng, Yajuan,Wang, Zhen,Xie, Zhixiang
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supporting information
p. 6573 - 6577
(2021/08/18)
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- P2X3 AND/OR P2X2/3 COMPOUNDS AND METHODS
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The present disclosure provides novel compounds and methods for preparing and using these compounds. In one embodiment, the compounds are of the structure of formula (I), wherein R1-R7 are defined herein. In a further embodiment, these compounds are useful in method for regulating one or both of the P2X3 or P2X2/3 receptors. In another embodiment, these compounds are useful for treating pain in patients by administering one or more of the compounds to a patient. In another embodiment, these compounds are useful for treating respiratory dysfunction in patients by administering one or more of the compounds to a patient.
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Paragraph 0225-0228
(2018/04/17)
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- Asymmetric synthesis of (+)-vertine and (+)-lythrine
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The total syntheses of the Lythracea alkaloids (+)-vertine and (+)-lythrine are described. Enantioenriched pelletierine is used as a chiral building block and engaged into a two step pelletierine condensation leading to two quinolizidin-2-one diastereomers in a 8:1 ratio. The major product is used in the synthesis of (+)-vertine via aryl-aryl coupling and ring closing metathesis to provide a Z-alkene α to the lactone carbonyl function. The same procedure was used for (+)-lythrine after base induced epimerization of the main quinolizidin-2-one diastereomer. Alternative classical ring closure strategies like macrolactonisation or aryl-aryl coupling failed.
- Chausset-Boissarie, La?titia,àrvai, Roman,Cumming, Graham R.,Guénée, Laure,Kündig, E. Peter
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supporting information; experimental part
p. 6473 - 6479
(2012/09/08)
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- New Synthetic Applications of Water-Soluble Acetate Pd/TPPTS Catalyst Generated in Situ. Evidence for a True Pd(0) Species Intermediate
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Studies on the sp-sp intermolecular coupling reactions with the palladium water-soluble catalyst prepared in situ from palladium(II) acetate and sulfonated triphenylphosphine P(C6H4-m-SO3Na)3 (TPPTS) in a homogeneous acetonitrile-water system, without Cu(I) promotor, afford diynes with moderate yields (45-65percent).Under the same conditions, the sp2-sp coupling of 2-iodophenols or 2-iodoanilines and terminal alkynes followed by intramolecular cyclization gives indolic and furanic products in good yields (60-99percent).Under these aqueous conditions, an efficient and short synthesis of eutypine illustrated the synthetic potentiality of the coupling.Furthermore, through a series of kinetic and 31P NMR experiments, we have demonstrated that a mixture of Pd(OAc)2 and TPPTS affords spontaneously a palladium(0) complex, through formation of bivalent complex Pd(OAc)2(TPPTS)2.A detailed mechanism of the reaction has been investigated thoroughly and the pertinent rate constants measured.The resulting palladium(0) complex reacts with phenyl iodide via an oxidative addition.This complex is considerably less reactive than the corresponding complex generated from PPh3, probably due to steric effects.
- Amatore, Christian,Blart, Errol,Genet, Jean Pierre,Jutand, Anny,Lemaire-Audoire, Sandrine,Savignac, Monique
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p. 6829 - 6839
(2007/10/03)
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- The Synthesis of Natural Acetylenic Compounds from Eutypa lata (Pers:F.) TUL.
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The synthesis of a series of novel acetylenic compounds 1-7, isolated recently from the fungus Eutypa lata, is described.The crucial step is the coupling reaction between protected aryl halogenide and the acetylenic chain as a cuprous acetylide (Scheme I).A more efficient method using bis(triphenylphosphine)palladium dichloride () as catalyst was also carried out with success.
- Defranq, Eric,Zesiger, Thierry,Tabacchi, Raffaele
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p. 425 - 430
(2007/10/02)
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