7-Siloxy-Substituted Hexahydronaphthalene Derivatives: Samarium Diiodide Promoted Synthesis and Typical Reactions

Synthesis ◽  
2020 ◽  
Vol 52 (18) ◽  
pp. 2721-2730
Author(s):  
Hans-Ulrich Reissig ◽  
André Niermann
Keyword(s):  
Reductive Cyclization ◽  
Samarium Diiodide ◽  
Double Bonds ◽  
Enol Ether ◽  
Silyl Enol Ether ◽  
Aryl Ketones

The samarium diiodide promoted reductive cyclization of a series of γ-aryl ketones with acetoxy, alkoxy, and siloxy groups in ortho-, meta-, and para-positions was investigated. Only precursors with p-acetoxy, p-tert-butoxy, or p-siloxy substituents furnished decent yields of the desired 7-oxy-1,2,3,4,6,8a-hexahydronaphthalene derivatives. The products were formed without contamination with the regio­isomeric bicyclic products containing conjugated double bonds. Typical reactions exploiting the silyl enol ether moiety of the 7-(tert-butyl­dimethylsiloxy)-1,2,3,4,6,8a-hexahydronaphthalene derivative were performed, allowing stereoselective access to highly substituted hexahydro­-, octahydro-, or decahydronaphthalene derivatives.

Diacetoxyiodobenzene Promoted Chlorination of Silyl Enol Ether of Aryl Ketones

2016 ◽  
Vol 36 (5) ◽  
pp. 1028 ◽  
Author(s):  
Xiaowei Chen ◽  
Siying Chong ◽  
Ganggang Du ◽  
Danfeng Huang ◽  
Kehu Wang ◽  
...  
Keyword(s):  
Enol Ether ◽  
Silyl Enol Ether ◽  
Aryl Ketones

The Gin Synthesis of Neofinaconitine

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Organic Synthesis ◽  
Oxidative Cleavage ◽  
Diels Alder ◽  
Reductive Cyclization ◽  
Cancer Center ◽  
Enol Ether ◽  
Norditerpenoid Alkaloids ◽  
Silyl Enol Ether ◽  
Sterically Demanding ◽  
Hydrolysis Of

The hexacyclic norditerpenoid alkaloids, including neofinaconitine 4, isolated from traditional Chinese and Japanese antiarrhythmics and analgesics, have long offered a challenge to organic synthesis. The late David Y. Gin of the Memorial Sloan-Kettering Cancer Center envisioned (J. Am. Chem. Soc. 2013, 135, 14313) an approach to 4 by way of the Diels–Alder coupling of 1 and 2. This project was completed under the supervision of his colleague Derek S. Tan. The cyclopropene 6 was prepared from the ester 5. Addition of 6 to the diene derived from 7 proceeded with modest regioselectivity to give, after enol ether hydrol­ysis, the ketone 8. After two-carbon extension of the ketone with 9 to the ester 10, ionization with HBr led to 11, that was carried on the diene 1. Opening of caprolactam 12 with ethylamine followed by oxidation delivered the aldehyde 13. Acid-mediated cyclization to the enamide followed by bromination gave 14. Carbomethoxylation followed by selenylation and oxidation completed the prep­aration of the dienophile 2. With the sterically-demanding Br blocking one face of the diene, Diels–Alder cycloaddition of 2 to 1 proceeded with high diastereocontrol, leading after hydrolysis of the intermediate silyl enol ether to the ketone 15. Oxidative cleavage of the more accessible alkene followed by elimination led to the ketone 16, that on exposure to acid underwent Mannich cyclization. Oxidation followed by elimination completed the preparation of 17. Reductive cyclization to 18 established the sixth and last ring of 4, but the tertiary alcohol was lacking. This was installed by selenylation followed by oxidation, presumably by way of the transient anti-Bredt enone. There are two classes of the norditerpenoid alkaloids, having 18 and 19 carbons respectively. The ester 19 could be a versatile precursor to both classes. For 4, the carbon had to be removed. Reduction and protection followed by oxidative cleavage gave 20, that was carried on to neofinaconitine 4.

Synthesis of α-Arylcarboxylic Acid Amides from Silyl Enol Ether via Migratory Amidation with 2-Azido-1,3-dimethylimidazolinium Hexafluorophosphate

2013 ◽  
Vol 42 (7) ◽  
pp. 691-693 ◽  
Author(s):  
Mitsuru Kitamura ◽  
Kento Murakami ◽  
Yuichiro Shiratake ◽  
Tatsuo Okauchi
Keyword(s):  
Enol Ether ◽  
Silyl Enol Ether

Carbon-carbon bond formation in reactions of PhIO.cntdot.HBF4-silyl enol ether adduct with alkenes or silyl enol ethers

1989 ◽  
Vol 54 (11) ◽  
pp. 2605-2608 ◽  
Author(s):  
V. V. Zhdankin ◽  
M. Mullikin ◽  
Rik Tykwinski ◽  
Bruce Berglund ◽  
Ronald Caple ◽  
...  
Keyword(s):  
Bond Formation ◽  
Enol Ether ◽  
Enol Ethers ◽  
Carbon Bond ◽  
Silyl Enol Ethers ◽  
Carbon Carbon Bond ◽  
Silyl Enol Ether

An Access to Highly Enantioenriched cis-3,5-Disubstituted γ-Lactones from α-Bromoacetate and Silyl Enol Ether

2021 ◽  
Author(s):  
Ha Rim Lee ◽  
Seo Yun Kim ◽  
Min Ji Park ◽  
Yong Sun Park
Keyword(s):  
Nucleophilic Substitution ◽  
Enol Ether ◽  
Enol Ethers ◽  
Silyl Enol Ethers ◽  
Synthetic Strategy ◽  
Silyl Enol Ether

A novel synthetic strategy for highly enantioenriched cis-3,5-disubstituted γ-lactones has been developed by the AgOTf-promoted nucleophilic substitution of α-bromoacetates with silyl enol ethers and subsequent reductive lactonization. The utility of...

Silyl Enol Ether Based Nucleophiles

2012 ◽  
pp. 1
Author(s):  
D. W. C. MacMillan ◽  
A. J. B. Watson
Keyword(s):  
Enol Ether ◽  
Silyl Enol Ether
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