Synthesis of (.+-.)-coronafacic acid. Efficient intramolecular Diels-Alder reaction of latent diene-dienophile functionality via thermal reaction

1980 ◽  
Vol 102 (20) ◽  
pp. 6353-6355 ◽  
Author(s):  
Akitami Ichihara ◽  
Ryoji Kimura ◽  
Seiichiro Yamada ◽  
Sadao Sakamura
1994 ◽  
Vol 49 (4) ◽  
pp. 542-550 ◽  
Author(s):  
Gerhard Himbert ◽  
Dieter Fink

While the S-alkyl- or S-phenyl-2,3-butadienethioates 4 a-c are synthesized via the usual “Wittig ylide way”, the corresponding 2-methyl-2,3-butadienethioates 9 a-d and the 2-methyl-4.4-diphenyl-2,3-butadienethioates 9 e,f are obtained by condensation of the allenic acids 7 a,b with the thiols and thiophenols 8 in the presence of dicyclohexylcarbodiimide (DCC) and a catalytic am ount of 4-dimethylaminopyridine (DMAP). In contrast to N- or O-phenyl 2,3- butadienamides or -esters, resp., the phenyl derivatives of 4 and 9 do not undergo the intram olecular Diels-Alder reaction, but by heating, all representatives of 4 only decompose, while 9 a-d and 9 e,f rearrange to 3-alkyl(aryl)thio-2-cyclobuten-1-ones 12a-d and to 3-arylthio- 1-naphthols 14a, b, resp. Heating of the cyclobutenone 12d in the presence of N-methylaniline furnishes the 2-butenanilide 16. On reacting 1-phenylthio-1-propyne 17 with diphenylketene 18, the diphenylacetate 19 is isolated, where the naphthol derivative 14a represents the ester moiety.


2020 ◽  
Vol 56 (76) ◽  
pp. 11247-11250
Author(s):  
Michael A. Frasso ◽  
Albert E. Stiegman ◽  
Gregory B. Dudley

Selective microwave heating in a viscous solvent accelerates a thermal reaction beyond temperature-based expectations.


1993 ◽  
Vol 71 (7) ◽  
pp. 995-1001 ◽  
Author(s):  
Peter Yates ◽  
N.K. Bhamare ◽  
Thierry Granger ◽  
T.S. Macas

Ethyl E-5-(4-ethyl-2-hydroxyphenyl)-2-pentenoate (7), prepared in four steps from m-ethylphenol (9), was converted via Wessely oxidation with lead tetraacetate followed by intramolecular Diels–Alder reaction in boiling xylene to ethyl 1-acetyloxy-6-ethyl-2,3,3a,4,5,7a-hexahydro-8-oxo-1,5-methano-1H-indene-anti-4-carboxylate (16). Hydrogenation of 16 followed by mild hydrolysis gave ethyl 6-ethyloctahydro-1-hydroxy-8-oxo-1,5-methano-1H-indene-anti-4-car-boxylate (24), which on oxidation with periodate gave 4-(ethoxycarbonyl)-6-ethyloctahydro-1-oxo-1H-indene-5-car-boxylic acid (26). Oxidative decarboxylation of this gave a mixture of ethyl 6-ethyl-2,3,3a,6,7,7a-hexahydro-1-oxo-1H-indene-4-carboxylate (31) and ethyl 6-ethyl-2,3,3a,4,7,7a-hexahydro-1-oxo-1H-indene-4-carboxylate (32); the latter was converted to the former by ethanolic sodium ethoxide. Hydrolysis of 31 with hot hydrochloric acid gave (±)-coronafacic acid (4).


Synlett ◽  
1989 ◽  
Vol 1989 (01) ◽  
pp. 30-32
Author(s):  
Thomas V. Lee ◽  
Alistair J. Leigh ◽  
Christopher B. Chapleo

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