101978-85-2Relevant articles and documents
Iridium-catalyzed asymmetric hydrogenation of racemic α-substituted lactones to chiral diols
Yang, Xiao-Hui,Yue, Hai-Tao,Yu, Na,Li, Yi-Pan,Xie, Jian-Hua,Zhou, Qi-Lin
, p. 1811 - 1814 (2017)
We report a protocol for the highly efficient iridium-catalyzed asymmetric hydrogenation of racemic α-substituted lactones via dynamic kinetic resolution. Using Ir-SpiroPAP (R)-1d as a catalyst, a wide range of chiral diols were prepared in a high yield (80-95%) with a high enantioselectivity (up to 95% ee) under mild reaction conditions. This protocol was used for enantioselective syntheses of (?)-preclamol and a chiral 2,5-disubstituted tetrahydropyran.
Cobalt versus Osmium: Control of Both trans and cis Selectivity in Construction of the EFG Rings of Pectenotoxin 4
Roushanbakhti, Ahria,Liu, Yifan,Winship, Paul C. M.,Tucker, Michael J.,Akhtar, Wasim M.,Walter, Daryl S.,Wrigley, Gail,Donohoe, Timothy J.
, p. 14883 - 14887 (2017)
Catalytic oxidative cyclisation reactions have been employed for the synthesis of the E and F rings of the complex natural product target pectenotoxin 4. The choice of metal catalyst (cobalt- or osmium-based) allowed for the formation of THF rings with either trans or cis stereoselectivity. Fragment union using a modified Julia reaction then enabled the synthesis of an advanced synthetic intermediate containing the EF and G rings of the target.
Chemo-biological preparation of the chiral building block (R)-4-acetoxy-2-methyl-1-butanol using Pseudomonas putida
Kim, Youngju,Watanabe, Hidenori,Kim, Bieong-Kil,Seu, Young-Bae
, p. 1658 - 1661 (2011)
In order to develop new methyl substituted chiral building blocks which are useful for the synthesis of methyl branched natural products, the enantioselective bioreduction of an exo-methylene to a methyl group was investigated. 4-Acetoxy-2-methylene-1-butanol 3 was prepared from itaconic acid over four steps and converted to the chiral alcohol (R)-4-acetoxy-2-methyl-1- butanol 4, by growing cells of Pseudomonas putida. The bioconversion achieved a high enantioselectivity (92% ee) and a high chemical yield (65%) within a relatively short reaction time (18-20 h). Copyright
Synthesis and complete structure determination of a sperm-activating and -attracting factor isolated from the ascidian ascidia sydneiensis
Watanabe, Tomohiro,Shibata, Hajime,Ebine, Makoto,Tsuchikawa, Hiroshi,Matsumori, Nobuaki,Murata, Michio,Yoshida, Manabu,Morisawa, Masaaki,Lin, Shu,Yamauchi, Kosei,Sakai, Ken,Oishi, Tohru
, p. 985 - 997 (2018)
For the complete structure elucidation of an endogenous sperm-activating and -attracting factor isolated from eggs of the ascidian Ascidia sydneiensis (Assydn-SAAF), its two possible diastereomers with respect to C-25 were synthesized. Starting from ergosterol, the characteristic steroid backbone was constructed by using an intramolecular pinacol coupling reaction and stereoselective reduction of a hydroxy ketone as key steps, and the side chain was introduced by Julia-Kocienski olefination. Comparison of the NMR data of the two diastereomers with those of the natural product led to the elucidation of the absolute configuration as 25S; thus the complete structure was determined and the first synthesis of Assydn-SAAF was achieved.
Simple synthesis of both enantiomers of 3-methyl-N-(3-methylbutyl)pyrrolidine
Veith, Hans Juergen,Collas, Markus,Zimmer, Reinhold
, p. 391 - 394 (1997)
(S)-3-Methyl-N-(3-methylbutyl)pyrrolidine (1) and its anti-pode (R)-1 have been prepared by reduction of (S)-4,5-dihydro-3-methyl-2(3H)furanone (7) and dimethyl (R)-2-methylsuccinate (11), bromination thereof, and ring closure of the intermediates (S)-9 and R)-9, respectively, with 3-methylbutylamine (10). An alternative synthesis of (A)-1 by mesylation of (R)-8 is also described. Both enantiomers of 1 were obtained in excellent enantiomeric excesses (ee = 96%). VCH Verlagsgesellschaft mbH, 1997.
Facile synthesis of versatile enantioenriched α-substituted hydroxy esters through a Bronsted acid catalyzed kinetic resolution
Qabaja, Ghassan,Wilent, Jennifer E.,Benavides, Amanda R.,Bullard, George E.,Petersen, Kimberly S.
, p. 1266 - 1269 (2013/05/09)
An efficient synthesis of enantioenriched α-substituted γ-hydroxy esters via a kinetic resolution event is described. Bulky racemic esters in the presence of a chiral Bronsted acid selectively lactonize to yield a recoverable enantioenriched hydroxy ester and lactone. These esters are highly versatile building blocks that can readily be converted to synthetically useful materials.
Using heteroaryl-lithium reagents as hydroxycarbonyl anion equivalents in conjugate addition reactions with (S, S)-(+)-pseudoephedrine as chiral auxiliary; Enantioselective synthesis of 3-substituted pyrrolidines
Alonso, Beatriz,Ocejo, Marta,Carrillo, Luisa,Vicario, Jose L.,Reyes, Efraim,Uria, Uxue
, p. 614 - 627 (2013/03/13)
We have developed an efficient protocol for carrying out the stereocontrolled formal conjugate addition of hydroxycarbonyl anion equivalents to α,β-unsaturated carboxylic acid derivatives using (S,S)-(+)-pseudoephedrine as chiral auxiliary, making use of the synthetic equivalence between the heteroaryl moieties and the carboxylate group. This protocol has been applied as key step in the enantioselective synthesis of 3-substituted pyrrolidines in which, after removing the chiral auxiliary, the heteroaryl moiety is converted into a carboxylate group followed by reduction and double nucleophilic displacement. Alternatively, the access to the same type of heterocyclic scaffold but with opposite absolute configuration has also been accomplished by making use of the regio- and diastereoselective conjugate addition of organolithium reagents to α,β,γ,δ-unsaturated amides derived from the same chiral auxiliary followed by chiral auxiliary removal, ozonolysis, and reductive amination/intramolecular nucleophilic displacement sequence.
Direct regiospecific and highly enantioselective intermolecular α-allylic alkylation of aldehydes by a combination of transition-metal and chiral amine catalysts
Afewerki, Samson,Ibrahem, Ismail,Rydfjord, Jonas,Breistein, Palle,Cordova, Armando
, p. 2972 - 2977 (2012/04/11)
The first direct intermolecular regiospecific and highly enantioselective α-allylic alkylation of linear aldehydes by a combination of achiral bench-stable Pd0 complexes and simple chiral amines as co-catalysts is disclosed. The co-catalytic asymmetric chemoselective and regiospecific α-allylic alkylation reaction is linked in tandem with in situ reduction to give the corresponding 2-alkyl alcohols with high enantiomeric ratios (up to 98:2 e.r.; e.r.=enantiomeric ratio). It is also an expeditious entry to valuable 2-alkyl substituted hemiacetals, 2-alkyl-butane-1,4-diols, and amines. The concise co-catalytic asymmetric total syntheses of biologically active natural products (e.g., Arundic acid) are disclosed. Go organic! Direct intermolecular regiospecific and highly enantioselective α-allylic alkylation of linear aldehydes by a combination of achiral bench-stable Pd0 complexes and simple chiral amines as co-catalysts is disclosed (see scheme). Copyright
INDANE ESTROGEN RECEPTOR MODULATORS AND USES THEREOF
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Page/Page column 94-95, (2012/01/06)
Described herein are compounds that are estrogen receptor modulators. Also described are pharmaceutical compositions and medicaments that include the compounds described herein, as well as methods of using such estrogen receptor modulators, alone and in combination with other compounds, for treating diseases or conditions that are mediated or dependent upon estrogen receptors.
ESTROGEN RECEPTOR MODULATORS AND USES THEREOF
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Page/Page column 105; 106, (2012/01/05)
Described herein are compounds that are estrogen receptor modulators. Also described are pharmaceutical compositions and medicaments that include the compounds described herein, as well as methods of using such estrogen receptor modulators, alone and in combination with other compounds, for treating diseases or conditions that are mediated or dependent upon estrogen receptors.