- Kinetic Resolution of Allylic Alcohol with Chiral BINOL-Based Alkoxides: A Combination of Experimental and Theoretical Studies
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The development and characterization of enantioselective catalytic kinetic resolution of allylic alcohols through asymmetric isomerization with chiral BINOL derivatives-based alkoxides as bifunctional Br?nsted base catalysts were described in the study. A number of chiral BINOL derivatives-based alkoxides were synthesized, and their structure-enantioselectivity correlation study in asymmetric isomerization identified a promising chiral Br?nsted base catalyst, which afforded various chiral secondary allylic alcohols (ee up to 99%, S factor up to >200). In the mechanistic study, alkoxide species were identified as active species and the phenol group of BINOL largely affected the high reactivity and enantioselectivity via hydrogen bonding between the chiral Br?nsted base catalyst and substrates. The strategy is the first successful synthesis strategy of various chiral secondary allylic alcohols through enantioselective transition-metal-free base-catalyzed isomerization. The applicability of the strategy had been demonstrated by the synthesis of the bioactive natural product (+)-veraguensin.
- Liu, Yidong,Liu, Song,Li, Dongmei,Zhang, Nan,Peng, Lei,Ao, Jun,Song, Choong Eui,Lan, Yu,Yan, Hailong
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p. 1150 - 1159
(2019/01/11)
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- Bioinspired total synthesis of tetrahydrofuran lignans by tandem nucleophilic addition/redox isomerization/oxidative coupling and cycloetherification reactions as key steps
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A very short three-step approach to trans,trans,trans-2,5-diaryl-3,4-dimethyltetrahydrofuran lignans is reported. The carbon skeleton is assembled in a single step based on an unprecedented tandem reaction consisting of 1,2-addition of aryllithium reagents to α,β-unsaturated aldehydes, ruthenium-catalyzed redox isomerization of the resulting alkoxides to enolates and their dimerization triggered by single electron oxidation. The resulting 2,3-dialkyl-1,4-diketones form with moderate to good d/l-diastereoselectivity and are transformed to the target tetrahydrofuran lignans by reduction and diastereoselective cycloetherification.
- Jagtap, Pratap R.,Císa?ová, Ivana,Jahn, Ullrich
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supporting information
p. 750 - 755
(2018/02/09)
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- Synthesis of nordihydroguaiaretic acid derivatives and their bioactivities on S. pombe and K562 cell lines
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Nordihydroguaiaretic acid (NDGA) and its synthetic analogues are potentially useful in treating diseases related to cancers, diabetes, viral and bacterial infections, and inflammation. In this paper, we report the optimal synthetic methods and the bioactivity study of terameprocol 2, NDGA derivative 3, and its cyclized analogue 4. The IC50 of these three compounds 2, 3 and 4 on the growth metabolism of Schizosacchromyces pombe and K562 cell lines were determined by microcalorimetry. The preliminary results showed that the compounds 2, 3 and 4 possessed good inhibition activities on S. pombe and K562 cell lines, and exhibited bidirectional biological effect and Hormesis effect. In particular, terameprocol 2 was found to possess the most potent inhibitory effect on K562 cell lines.
- Li, Xu,Jiang, Jian-Hong,Chen, Qingqi,Xiao, Sheng-Xiong,Li, Chuan-Hua,Gu, Hui-Wen,Zhang, Hui,Hu, Ji-Lin,Yao, Fei-Hong,Li, Qiang-Guo
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p. 605 - 613
(2013/06/05)
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- An asymmetric route to total synthesis of the furano lignan (+)-veraguensin
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Total synthesis of the furano lignan (+)-veraguensin is described. The key steps involve a diastereoselective aldol-type condensation of an ester enolate having an α-chiral center with an aromatic aldehyde and a novel isomerization of the syn vicinal subs
- Matcha, Kiran,Ghosh, Subrata
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p. 6924 - 6927
(2011/03/18)
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- Tetrahydrofuran lignans via tandem oxidative anionic-radical processes or reductive radical cyclizations
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Several tetrahydrofuran lignans have become important due to their diverse biological activities. We present initial studies on short syntheses of some of the simplest members of this natural product class. Galgravin and Veraguensin are obtained in only t
- Jahn, Ullrich,Rudakov, Dmytro
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p. 4481 - 4484
(2007/10/03)
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- O-demethylation of 7,7'-epoxylignans by Aspergillus niger
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Biotransformation of the 7,7'-epoxylignans, (+)-veraguensin, (+)- galbelgin and galgravin by Aspergillus niger has been investigated. These lignans were converted to their corresponding 4,4'-O-demethyl derivatives, (+)-verrucosin, (+)-fragransin A2/
- Kasahara, Hiroyuki,Miyazawa, Mitsuo,Kameoka, Hiromu
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p. 111 - 113
(2007/10/03)
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- 2,5-DIARYL-3,4-DIMETHYLTETRAHYDROFURANOID LIGNANS
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Key Word Index - Aristolochia chilensis; Aristolochiaceae; Magnoliales; (+)-aristolignin; (-)-zuonin-A; malabaricanol.Aristolochia chilensis has yielded the new 2,5-diaryl-3,4-dimethyltetrahydrofuranoid lignans (+)-aristolignin and (-)-zuonin-A.These and related tetrahydrofuranoids have been classified into six stereochemical groups.
- Urzua, Alejandro,Freyer, Alan J.,Shamma, Maurice
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p. 1509 - 1512
(2007/10/02)
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- Structure of Malabaricanol - A Lignan from the Aril of Myristica malabarica Lam.
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Malabaricanol, a lignan isolated from Myristica malabarica has been assigned the structure as β,β'-dimethyl-α,α'-bis(4-hydroxy-3-methoxyphenyl)tetrahydrofuran by spectroscopic and chemical methods.
- Purushothaman, K. K.,Sarada, A.,Connolly, J. D.
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- MANASSANTINS A/B AND SAUCERNEOL: NOVEL BIOLOGICALLY ACTIVE LIGNOIDS FROM SAURURUS CERNUUS
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From the extract of Saururus cernuus two toxic principles, manassantins A and B and a related substance, saucerneol, were isolated.They have novel dineolignan or sesquineolignan type structures.Although toxic, manassantin A showed potential neuroleptic activity.
- Rao, Koppaka V.,Alvarez, Francisco M.
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p. 4947 - 4950
(2007/10/02)
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