E,E- and E,Z-α-phenyl-α′-acetoxyorthoquinodimethane: steric and electronic control of cycloaddition reactions

1986 ◽  
Vol 64 (4) ◽  
pp. 793-798 ◽  
Author(s):  
James L. Charlton ◽  
Mian M. Alauddin ◽  
Glenn H. Penner

E,E- and E,Z-α-phenyl-α′-acetoxyorthoquinodimethanes have been prepared from the corresponding cis- and trans-1-acetoxy-3-phenyl-1,3-dihydrobenzo[c]thiophene-2,2-dioxides. The regio- and diastereoselectivity of the addition reactions with dimethyl fumarate, dimethyl maleate, maleic anhydride, and methyl crotonate have been determined. Abinitio calculations have been carried out on orthoquinodimethane and its α-phenyl and α-oxy derivatives. A correlation has been made between the steric and electronic properties of the orthoquinodimethanes and the regio- and diastereoselectivity of their Diels–Alder reactions.

1993 ◽  
Vol 46 (10) ◽  
pp. 1613 ◽  
Author(s):  
A Menzek ◽  
M Balci

Diels-Alder cycloadditions of dienophiles , such as 4-phenyl-1,2,4-triazoline-3,5-dione, dimethyl acetylenedicarboxylate, dimethyl fumarate , diethyl azodicarboxylate , maleic anhydride, benzyne and p-benzoquinone, to dimethyl trans-3,8-dihydrohexalene-3,8-dicarboxylate (4) have been investigated, and monoaddition products (9)-(16) have been isolated. It has been shown that a second addition to this system occurs only with singlet oxygen and with benzyne. Furthermore, it has been established that the second addition is retarded because of the strain in the cycloheptatriene molecule. The anti bicyclic endoperoxides (21)-(25) formed have been converted, either on heating or in a Co( tpp )- catalysed reaction, into the corresponding bisepoxides (27)-(31).


1993 ◽  
Vol 71 (9) ◽  
pp. 1463-1483 ◽  
Author(s):  
Edward Piers ◽  
Richard W. Friesen ◽  
Paul Kao ◽  
Steven J. Rettig ◽  
James Trotter

The results of a study of Diels–Alder reactions of the bicyclic dienes 6–8 with a variety of dienophiles are reported. Although 6 and 7 undergo cycloaddition reactions smoothly and efficiently, thermal Diels–Alder reactions of 8 are generally sluggish or, under the conditions investigated, do not proceed at all. Additions of tetracyanoethylene (TCNE) to 6–8 are highly face-selective, with preferential attack of the dienophile on the side of the dienes opposite to the angular methoxycarbonyl group. Reaction of 7 with maleic anhydride (MAN) is completely face-selective and proceeds preferentially via an endo transition state. Diels–Alder reactions of 6 and 7 with methyl acrylate (MAC) and nitroethylene (NE) are entirely regioselective, but the face-selectivities, which vary from ~2:1 to ~3:1, are rather low. The use of this chemistry as a method for the synthesis of functionalized, stereochemically defined, perhydro-1H-phenalenes is demonstrated.


1986 ◽  
Vol 64 (4) ◽  
pp. 720-725 ◽  
Author(s):  
James L. Charlton

The extent of asymmetric induction in the bimolecular Diels–Alder reactions of chiral o-quinodimethanes with dimethyl fumarate, methyl acrylate, and maleic anhydride has been studied. o-Quinodimethanes with chiral α-alkoxy groups were prepared from 1-alkoxy-1,3-dihydrobenzo[c]thiophene-2,2-dioxides 4a–f or 1-alkoxy-3-phenyl-1,3-dihydrobenzo[c]thiophene-2,2-dioxides 4g–h by thermolysis. These alkoxybenzosulfones were prepared from the corresponding hydroxybenzosulfones 8 and 1-phenylethanol, 2-phenyl-1-propanol, 4-phenyl-2-butanol, 1-phenyl-2-propanol, 3,3-dimethyl-2-butanol, or 1-cyclo-hexylethanol. The 1-phenylethoxy substituent yielded the largest asymmetric induction. The absolute configurations of the major cycloadducts of methyl acrylate with the o-quinodimethanes generated from 1-(R- 1-phenylethoxy)- and 1-(S-1-phenylethoxy)-1,3-dihydrobenzo[c]thiophene-2,2-dioxides 4i and 4j have been determined to be 1S,2S-1-(R-1-phenylethoxy)- and 1R,2R-1-(S-1-phenylethoxy)-2-carbomethoxy-1,2,3,4-tetrahydronaphthalene 11i and 11j, respectively. The proposition that a chiral alkoxy substituent can block one face of the o-quinodimethane towards addition of a dienophile is discussed.


Tetrahedron ◽  
1978 ◽  
Vol 34 (24) ◽  
pp. 3525-3530 ◽  
Author(s):  
A. Robert ◽  
M. Baudy ◽  
A. Foucaud ◽  
L. Golic ◽  
B. Stanovnik

1979 ◽  
Vol 57 (3) ◽  
pp. 314-317 ◽  
Author(s):  
John N. Bridson

N-3′-Furylbenzamide gives a conventional Diels–Alder adduct with maleic anhydride but with dimethyl maleate and methyl acrylate further reactions take place at the enamide grouping of the initially formed adducts. Compounds have been isolated in which molecules of an alcohol, used as solvent, or the starting furan have added to the double bond of the 1:1 adducts. In the first case unstable alkoxyamides are formed; in the second stable 2:1 adducts result from a novel uncatalysed addition to the double bond of the enamide. The stereochemistry of these and related compounds is discussed.


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