Sterically Hindered Aromatic Compounds. III. Acid-catalyzed Reactions of 2,4,6-Tri-t-butyl- and 2-Methyl-4,6-di-t-butylbenzyl Alcohols and Chlorides

1972 ◽  
Vol 50 (2) ◽  
pp. 281-290 ◽  
Author(s):  
L. R. C. Barclay ◽  
H. R. Sonawane ◽  
M. C. MacDonald

Treatment of 2,4,6-tri-t-butylbenzyl alcohol (2), the corresponding benzyl chloride (3) and methyl ether (5) with strong acids gave high yields of 1,1-dimethyl-4,6-di-t-butylindane (10). On the other hand, acid-catalyzed reactions on 2-methyl-4,6-di-t-butylbenzyl alcohol (13), chloride (16), and methyl ether (12) yielded nucleophilic substitution products. According to comparative hydride transfer reactions between triethylsilane and carbonium ions generated from 2, 3, 13, and 16 in trifluoroacetic acid, the 2,4,6-tri-t-butylbenzyl cation is very readily formed. A mechanism suggested for the formation of 10 involves this cation as an intermediate.

2012 ◽  
Vol 2 (1) ◽  
pp. 129-138 ◽  
Author(s):  
Norio Ota ◽  
Yasuhiro Kamitori ◽  
Ryusuke Shirai ◽  
Mizuki Hatakenaka ◽  
Etsuji Okada

2011 ◽  
Vol 7 ◽  
pp. 606-614 ◽  
Author(s):  
Leping Liu ◽  
Bo Xu ◽  
Gerald B Hammond

During the last decade, gold-catalyzed reactions have become a tour de force in organic synthesis. Recently, the gold-, Brønsted acid- or Lewis acid-catalyzed oxygen transfer from carbonyl to carbon–carbon triple bond, the so-called alkyne–carbonyl metathesis, has attracted much attention because this atom economical transformation generates α,β-unsaturated carbonyl derivatives which are of great interest in synthetic organic chemistry. This mini-review focuses on the most recent achievements on gold-catalyzed oxygen transfer reactions of tethered alkynones, diynes or alkynyl epoxides to cyclic enones. The corresponding mechanisms for the transformations are also discussed.


1962 ◽  
Vol 40 (1) ◽  
pp. 122-127 ◽  
Author(s):  
J. M. Pepper ◽  
B. P. Robinson ◽  
G. W. Schwanbeck

A detailed study of the nature, and the mechanism of formation, of the products of the aluminum chloride catalyzed reaction of vinyl esters and benzene has been initiated. Using vinyl acetate the formation of the previously reported acetophenone, 1,1-diphenylethane, and 9,10-dimethylanthracene has been confirmed. By means of both column chromatography and thermal distillation, a similar carbonyl-containing fraction was obtained which, as a result of a gas chromatographic study, has been shown to be a mixture of six compounds. Of these, the two major components have been identified as acetophenone and p-ethylacetophenone, the latter previously unreported as a product of this reaction.The reaction of vinyl formate and benzene has been studied for the first time. High yields of 9,10-dimethylanthracene were obtained but no carbonyl-containing compounds. A study of the effect of a variation in molar ratio of benzene to vinyl acetate indicated that a maximum yield of 9,10-dimethylanthracene was obtained using a 6:1 molar ratio.The significance of these results is discussed.A method has been devised for an improved synthesis of 9,10-dimethylanthracene. The generality of this procedure for the synthesis of other substituted polynuclear compounds is indicated.


1986 ◽  
Vol 51 (10) ◽  
pp. 2167-2180 ◽  
Author(s):  
Lubor Fišera ◽  
Nadezhda D. Kozhina ◽  
Peter Oravec ◽  
Hans-Joachim Timpe ◽  
Ladislav Štibrányi ◽  
...  

3-Aryl-4-R-carbamoyl-5-hydroxymethylisoxazolines (IV) were synthesized by allowing R-NH2 amines with R = H, CH3, C3H7, C6H5C2H5, and NH2 to act on 3-(X-phenyl)-4-oxo-3a,4,6,6a-tetrahydrofuro[3,4-d]isoxazoles (III) with X = H, 4-CH3, 4-OCH3, 2-OCH3, 4-Cl, 2-Cl, 4-F, 2-F, 4-Br, 4-NO2, and 3-NO2. Exposed to radiation, the substances IV give Z-2-hydroxymethylamino-2-aryl-1-formylacrylamides (V) in good yields. The 4-Cl and 4-F substituted Z-derivatives V isomerize irreversibly to the E-derivatives VI if allowed to stand in solvent; the remaining derivatives V are stable. The quantum yields of the photoreaction are from 0.012 to 0.106 in dependence on the substituent X. In all cases where the compounds IV were used for the preparation of condensed heterocycles in conditions of acid-catalyzed reactions, lactones III were preferentially formed; the action of thionyl chloride on IV results in the formation of chloromethyl derivatives VIII, which do not undergo further cyclization.


Author(s):  
Mizzanoor Rahaman ◽  
M. Shahnawaz Ali ◽  
Khorshada Jahan ◽  
Damon Hinz ◽  
Jawad Bin Belayet ◽  
...  

Author(s):  
Emanuele Moioli ◽  
Leo Schmid ◽  
Peter Wasserscheid ◽  
Hannsjoerg Freund

The kinetics of the acid catalyzed reactions of acetaldehyde ammonia trimer (AAT) and paraldehyde (para) to 2-methyl-5-ethyl pyridine (MEP) in the presence of an acid catalyst were investigated systematically. A...


2021 ◽  
pp. 1-12
Author(s):  
Gerasimos M. Tsivgoulis ◽  
Dimitris G. Vachliotis ◽  
Golfo G. Kordopati ◽  
Panayiotis V. Ioannou

Sulfonates are well-known substances with a variety of applications, e.g. as surfactants. On the other hand, bis(sulfonates) bearing hydroxyl or keto group(s) in between the sulfonate groups can be used with or without further modification as starting materials for the preparation of new type of molecules capable to form either complexes or in general supramolecular structures. The synthesis of three hydroxyl-bearing bis(sulfonates), 2-hydroxypropane-1,3-bis(sodium sulfonate) 4, DL-2,3-dihydroxybutane-1,4-bis(sodium sulfonate) 8, and sodium 2,3,4-trihydroxy-1-sulfonate 7 (as by-product) via the Strecker sulfonation are described. Interestingly, under similar conditions, sulfonation of 1,4-dibromo-2,3-butanedione 9 was found to be very complicated and no pure product could be isolated, despite previously reported results on sulfonation of α-halogenated ketones in high yields. There are indications that SO3 2 -  attacks at the carbonyl carbon of 9 followed by rearrangement and expulsion of SO4 2 - . 1,4-dibromo-2,3-butanedione 9, bearing two keto groups next to methylene groups, can potentially exist as enols or in the case of its solution in hydroxylic solvents in the form of hemiketals or geminal diols. This behavior of 9 when is dissolved in CDCl3, CD3OD and D2O was studied by means of UV-Vis, 1H and 13C NMR and the nature of the adducts formed was elucidated.


1999 ◽  
Vol 23 (8) ◽  
pp. 470-471
Author(s):  
Motoo Tori ◽  
Masakazu Sono ◽  
Keiko Takikawa ◽  
Reiko Matsuda ◽  
Masao Toyota ◽  
...  

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.


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