- Unexpected regioselectivity in the synthesis of pyranonaphthoquinone via the diels-alder reaction
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The unusual regioselectivity In the Diels-Alder reactions of pyranoquinone 1 with (4,4-dlmethoxybuta-1,3-dlen-2-yloxy)trimethylsilane 2 are explored by both computations and experiments. The regioselectivity Is controlled by the electrostatic interaction of the lactone ring-oxygen and the vicinal quinone oxygen on the transition structure, which can be tuned by the terminal methyl group of the butadienes.
- Cui, Yi,Jiang, Hao,Li, Zhengtao,Wu, Na,Yang, Zhen,Quan, Junmin
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- PEG-polymer-supported liquid-phase combinatorial synthesis of structurally diverse 2,3-dihydro-4-pyridones
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A convenient liquid-phase synthetic protocol for the construction of structurally diverse 2,3-dihydro-4-pyridones on soluble polymer support by the aza Diels-Alder reaction has been developed, which utilized a one-pot three-component reaction of either PEG-supported amine, aromatic aldehydes and the Danishefsky's diene, or PEG-supported aldehyde, aromatic amines and Danishefsky's diene.
- Guo, Hongchao,Wang, Zheng,Ding, Kuiling
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- Enantioselective Formal [4+1] Cycloaddition of Diazoarylacetates and the Danishefsky's Diene: Stereoselective Synthesis of (-)-1,13-Herbertenediol
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Rodium chiral diene complex-catalyzed enantioselective cycloaddition of aryl α-diazoarylacetates and electron-enriched Danishefsky-type dienes afforded highly functionalized and optically enriched cyclopentenones in excellent yields (up to 97% yield) and
- Hu, Fang,Zhou, Qing,Cao, Fei,Chu, Wen-Dao,He, Long,Liu, Quan-Zhong
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- Total Synthesis of (±)-Furanether A
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The first total synthesis of (±)-furanether A, which exhibits good antifeedant activity, has been concisely achieved in 13 linear steps. Notably, the key rigid tetracyclic skeleton containing a 1-methyl-8-oxabicyclo[3.2.1]octane moiety with two vicinal quaternary carbon centers was rapidly constructed in one step through a unique tandem C-H oxidation/oxa-[3,3] Cope rearrangement/aldol cyclization sequence.
- Jin, Da-Ping,Gao, Zhu-Peng,Liu, Lin,Cao, Shi-Qi,Xu, Xue-Tao,Hou, Xue-Wei,Zheng, Tian-Lu,Jiang, Li-Ming,Zhu, Dao-Yong,Wang, Shao-Hua
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supporting information
p. 8843 - 8846
(2021/11/20)
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- Synthesis of a functionalized 7,6-bicyclic spiroimine ring fragment of the spirolides
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The asymmetric synthesis of a functionalized 7,6-spiroimine related to the spirolides is described. Intermolecular Diels-Alder cycloaddition of a chiral trisubstituted dienophile and Danishefsky's diene enabled simultaneous installation of the C7 and C29 stereocenters. Further transformations and late-stage aza-Wittig cyclization afforded the spiroimine in good yield. During this study, an unprecedented 14-membered dialdimine was also obtained.
- Gueret, Stephanie M.,Furkert, Daniel P.,Brimble, Margaret A.
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supporting information; experimental part
p. 5226 - 5229
(2011/02/23)
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- Synthesis and NMDA-receptor affinity of 4-oxo-dexoxadrol derivatives
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A synthesis of novel dexoxadrol analogues is described, which allows modifications of the piperidine substructure. The key step of the synthesis is a hetero Diels-Alder reaction of the imine 12 with Danishefsky's diene 6. After separation of the diastereo
- Sax, Michael,Ebert, Kirstin,Schepmann, Dirk,Wibbeling, Birgit,Wuensch, Bernhard
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p. 5955 - 5962
(2007/10/03)
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- One pot solid phase synthesis of 2-substituted 2,3-dihydropyridin-4(1H)- ones on Rinkamide-resin
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A novel solid phase synthesis of 2-substituted 2,3-dihydropyridin-4(1H)- ones using Rinkamide-polystyrene-resin is described. The key step involves a hetero-Diels-Alder reaction of Danishefsky's diene with solid phase bound imines, which was carefully opt
- Sax, Michael,Berning, Stefanie,Wünsch, Bernhard
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p. 205 - 211
(2007/10/03)
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- Chiral hetero Diels-Alder products by enantioselective and diastereoselective zirconium catalysis. Scope, limitation, mechanism, and application to the concise synthesis of (+)-prelactone C and (+)-9-deoxygoniopypyrone
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Catalytic asymmetric hetero Diels-Alder (HDA) reactions using a chiral zirconium complex have been developed. The reactions of aldehydes with Danishefsky's dienes proceeded smoothly to afford the corresponding pyranone derivatives in high yields with high diastereo- and enantioselectivities in the presence of a chiral zirconium complex, which was prepared from zirconium tert-butoxide, (R)-3,3′-diiodobinaphthol or its derivative, a primary alcohol, and a small amount of water. It is noted that 2,3-trans-pyranone derivatives were obtained with remarkably high diastereo- and enantioselectivities in the reaction with 4-methyl Danishefsky's diene. This is the first example of catalytic asymmetric trans-selective hetero Diels-Alder reactions of aldehydes. Furthermore, asymmetric HDA reactions with 4-benzyloxy Danishefsky's dienes were conducted to afford 2,3-cis-pyranone derivatives in high selectivities. Isolation of an intermediate of this asymmetric hetero Diels-Alder reaction indicated that the reaction proceeded in a stepwise cycloaddition pathway. Finally, these catalytic, asymmetric hetero Diels-Alder reactions were successfully applied to concise syntheses of biologically important natural pyranone derivatives, (+)-Prelactone C and (+)-9- deoxygoniopypyrone.
- Yamashita, Yasuhiro,Saito, Susumu,Ishitani, Haruro,Kobayashi, Shu
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p. 3793 - 3798
(2007/10/03)
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- An Efficient and Highly Chemoselective Method to Desilylate Silyl Ethers
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An efficient and highly chemoselective desilylating method is described.Trimethylsilyl ethers (0.25 M) in a CH3OH/CCl4 (1:1) solvent mixture are deprotected to their corresponding alcohols with ultrasound in a commercial ultrasonic cleaning bath.Selective deprotection of tert-butyldimethylsilyl ethers of benzyl alcohols and phenols is achieved under ultrasonic conditions.We deprotected also tert-butyldimethylsilyl ethers of primary alcohols, whereas tert-butyldimethylsilyl ethers of secondary and tertiary alcohols are stable under these conditions. - Key words: Sonochemistry; Ultrasound; Cavitation; Desilylation; Chemoselection; Deprotection.
- Lee, Adam Shih-Yuan,Yeh, Hsiu-Chih,Yeh, Ming-Kuo,Tsai, Ming-Hung
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p. 919 - 922
(2007/10/03)
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- ADDITION OF AMINOKETENE DITHIOACETALS TO α,β-UNSATURATED KETONES. SYNTHESIS AND REACTIONS OF CYCLOHEX-2-EN-1,4-DIONE MONODITHIOACETALS
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Aminoketene dithioacetals add to α,β-unsaturated ketones to give 1,5-diketones after hydrolytic work-up.Upon treatment with acid or base, these diketones suffer intramolecular aldol reactions yielding cyclohex-2-en-1,4-dione monodithioacetals, interesting and useful synthetic equivalents of cyclohex-2-en-1,4-diones which readily undego conjugate addition and cycloaddition reactions.
- Page, Philip C. Bulman,Harkin, Shaun A,Marchington, Allan P.,Niel, Monique B. van
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p. 3819 - 3838
(2007/10/02)
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- A NEW PRACTICAL SYNTHESIS OF SILYL ENOL ETHERS. II. FROM α,β-UNSATURATED ALDEHYDES AND KETONES
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In acetonitrile as the solvent and in the presence of a tertiary amine the trimethylchlorosilane/sodium iodide (trimethyliodosilane "in situ") reagent provides the corresponding siloxy dienes when reacted with α,β-unsaturated series.These reactions occurs
- Cazeau, P.,Duboudin, F.,Moulines, F.,Babot, O.,Dunogues, J.
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p. 2089 - 2100
(2007/10/02)
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