Flash thermolysis: multiple sigmatropic rearrangements in ortho-substituted aromatic compounds

1976 ◽  
Vol 54 (23) ◽  
pp. 3749-3756 ◽  
Author(s):  
Pierre de Champlain ◽  
Jean-Louis Luche ◽  
Robert A. Marty ◽  
Paul de Mayo
Keyword(s):  
Benzyl Alcohol ◽  
Methyl Ether ◽  
Aromatic Compounds ◽  
Sigmatropic Rearrangement ◽  
Methyl Anthranilate ◽  
Rearrangement Product ◽  
Sigmatropic Rearrangements

A number of o-disubstituted benzenoid substances on flash thermolysis undergo 1,4-elimination of water or alcohols to yield o-quinonoid derivatives. Those products possessing a pentadienyl hydrogen subsequently undergo a 1,5-sigmatropic rearrangement: in many cases the rearrangement product undergoes yet further transformations, such as addition or hydrolysis, and such reactions have been used for their characterization. Included are: the conversion of N-methyl anthranilate esters to o-aminobenzaldehyde; o-(N-methyl)benzyl alcohol and methyl ether to o-toluidine; o-methoxymethylformanilide to o-tolyl isocyanate; and o-carboxymethylformanilide to o-aminobenzaldehyde.

[3,3]- Versus [1,3]-Sigmatropic Rearrangement of O-Substituted Allyl N-Acylmonothiocarbamates

1994 ◽  
Vol 59 (12) ◽  
pp. 2650-2662 ◽  
Author(s):  
Vlastimír Ficeri ◽  
Peter Kutschy ◽  
Milan Dzurilla ◽  
Ján Imrich
Keyword(s):  
Double Bond ◽  
Benzyl Alcohol ◽  
Sigmatropic Rearrangement ◽  
Allylic Alcohols ◽  
Cinnamyl Alcohol ◽  
Aromatic System ◽  
Sigmatropic Rearrangements ◽  
Sigmatropic Shift

Substituted allylic alcohols (2-buten-1-ol, 1-buten-3-ol, cinnamyl alcohol and 3-methyl-2-buten-1-ol) react with acyl isothiocyanates (4-chlorobenzoyl, 2,6-difluorobenzoyl, 3-phenylpropenoyl, 2-thienocarbonyl, 3-chloro-2-thienocarbonyl and 3-chloro-2-benzo[b]thienocarbonyl isothiocyanate) with the formation of highly reactive O-substituted allyl N-acylmonothiocarbamates, which either spontaneously or by heating in boiling benzene undergo [3,3]-sigmatropic rearrangement to S-substituted allyl N-acylmonothiocarbamates. The structure of S-esters with isomerized allylic group affords the unequivocal evidence of the [3,3]-sigmatropic route of studied rearrangement. Further heating of [3,3]-rearranged N-(4-chlorobenzoyl)monothiocarbamates results in the [1,3]-sigmatropic shift of monothiocarbamate group. Using arylalkyl alcohols with the allylic double bond inserted into an aromatic system the obtained O-esters either do not undergo any rearrangement (benzyl alcohol) or undergo [1,3]-sigmatropic rearrangement (2- and 3-furylmethanol and 1-(2-furyl)ethanol) to the corresponding S-esters. For explanation of this reaction the tandem of [3,3]- and [1,3]-sigmatropic rearrangements is suggested.

scholarly journals Oxidation Reactions of Marchantin A Trimethyl Ether and Some Aromatic Compounds using m-Chloroperbenzoic Acid. Formation of Muconic Acid Ester and m-Chlorobenzoate

1999 ◽  
Vol 23 (8) ◽  
pp. 470-471
Author(s):  
Motoo Tori ◽  
Masakazu Sono ◽  
Keiko Takikawa ◽  
Reiko Matsuda ◽  
Masao Toyota ◽  
...  
Keyword(s):  
Aromatic Ring ◽  
Methyl Ether ◽  
Aromatic Compounds ◽  
Acid Ester ◽  
Acid Formation ◽  
Oxidation Reactions ◽  
Muconic Acid ◽  
Trimethyl Ether

On treatment with m-chloroperbenzoic acid, dihydroeugenol methyl ether and marchantin A trimethyl ether afford muconic acid ester derivatives by oxidation of the aromatic ring as well as hydroxylated derivatives; the m-chlorobenzoate of the dihydroeugenol derivative is also observed for the former.

Part 2: Efficient strategies for the construction of variably substituted bicyclo[5.3.1]undecenones (AB-taxane ring systems) and their conversion to tricyclo[9.3.1.03,8]pentadecenones (ABC taxane ring systems) and bicyclo[2.2.2]octanones

2004 ◽  
Vol 82 (2) ◽  
pp. 227-239 ◽  
Author(s):  
Nidia P Villalva-Servín ◽  
Alain Laurent ◽  
Alex G Fallis
Keyword(s):  
Lewis Acid ◽  
Sigmatropic Rearrangement ◽  
Diels Alder ◽  
Direct Access ◽  
Cope Rearrangement ◽  
Ring Closing Metathesis ◽  
Ring Systems ◽  
Sigmatropic Rearrangements ◽  
Key Words Magnesium ◽  
Cope Rearrangements

The extension of our strategies for the construction of cyclic molecules containing variably substituted bicyclo[5.3.1]undecenones (AB taxane ring systems) for the synthesis of the tricyclo[9.3.1.03,8]pentadecenone (ABC taxane ring system) and bicyclo[2.2.2]octanones are described. These routes employ a multi-component coupling protocol that employs sequential magnesium-mediated carbometallation of allyl-substituted propargyl alcohols followed by diastereoselective Lewis acid catalyzed intramolecular Diels–Alder reactions (IMDA). Subsequent ring-closing metathesis (RCM) afforded the ABC taxane core structure. Enone accelerated [3,3] sigmatropic rearrangements (Cope rearrangements) generated the bicyclo[2.2.2]octanone nucleus. In the presence of a Lewis acid, the dienophile precursor underwent a tandem reaction via the adduct directly to the bicyclo[2.2.2]octanones. This is the first example of a novel enone accelerated carbocycle Cope rearrangement and provides direct access to bicyclo[2.2.2]octanones by a new route that compliments the traditional cyclohexadiene cycloaddition approach. Key words: magnesium chelate, Lewis acid, taxanes, Diels–Alder, sigmatropic rearrangement, oxy-Cope, ring-closing metathesis, bicyclo[2.2.2]octanone.

Liquid phase benzylation of aromatic compounds with benzyl alcohol catalyzed by niobium phosphate

2003 ◽  
Vol 245 (2) ◽  
pp. 377-382 ◽  
Author(s):  
Marcus Henrique C. de la Cruz ◽  
João Francisco C. da Silva ◽  
Elizabeth R. Lachter
Keyword(s):  
Liquid Phase ◽  
Benzyl Alcohol ◽  
Aromatic Compounds ◽  
Niobium Phosphate

Nucleic acid related compounds. 77. 2′,3′-Didehydro-2′,3′-dideoxy-2′(and 3′)-methylnucleosides via [3,3]-sigmatropic rearrangements of 2′(and 3′)-methylene-3′(and 2′)-O-thiocarbonyl derivatives and radical reduction of a 2′-chloro-3′-methylene analogue

1993 ◽  
Vol 71 (2) ◽  
pp. 186-191 ◽  
Author(s):  
Vincente Samano ◽  
Morris J. Robins
Keyword(s):  
Nucleic Acid ◽  
Sigmatropic Rearrangement ◽  
Sigmatropic Rearrangements ◽  
Radical Reduction ◽  
Adenosine Derivatives ◽  
Related Compounds

Treatment of 5′-O-(tert-butyldiphenylsilyl)-2′(and 3′)-deoxy-2′(and 3′)-methyleneuridine (and adenosine) derivatives with phenyl chlorothionocarbonate gave the 3′(and 2′)-O-phenoxythiocarbonyl intermediates, which underwent spontaneous [3,3]-sigmatropic rearrangement to give the 2′,3′-didehydro-2′,3′-dideoxy-2′(and 3′)-(phenoxycarbonylthio)methyl analogues. These allylic thioesters were subjected to tributylstannane-mediated hydrodesulfurization and deprotection to give 2′,3′-didehydro-2′,3′-dideoxy-2′(and 3′)-methyluridine (and adenosine). Tributylstannane-mediated hydrodehalogenation of a 2′-chloro-2′,3′-dideoxy-3′-methyleneuridine derivative afforded the 2′,3′-didehydro-2′,3′-dideoxy-3′-methyl product of allylic transposition exclusively.

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