Stereochemical control by an allylic substitutent of an acyclic dienophile in the Diels-Alder reaction

1982 ◽  
Vol 104 (4) ◽  
pp. 1106-1107 ◽  
Author(s):  
Richard W. Franck ◽  
Thomas V. John ◽  
Kazimierz Olejniczak ◽  
John F. Blount







1980 ◽  
Vol 11 (48) ◽  
Author(s):  
S. G. PYNE ◽  
M. J. HENSEL ◽  
S. R. BYRN ◽  
A. T. MCKENZIE ◽  
P. L. FUCHS


1985 ◽  
Vol 63 (10) ◽  
pp. 2736-2741 ◽  
Author(s):  
William J. Leigh

The possibility of using liquid crystalline solvents to control the stereospecificity of bimolecular reactions as a result of differences in liquid crystalline solvation of the various possible transition states has been examined. The Diels–Alder reactions of 2,5-dimethyl-3,4-diphenylcyclopentadienone with four dienophiles of varying steric size (cyclopentene, cycloheptene, indene, and acenaphthylene) have been carried out in benzene, cholesteryl nonanoate (isotropic), cholesteryl propionate (cholesteric), and 4-ethyl-4′-(4-pentylcyclohexyl)biphenyl (smectic) at 105 °C. In spite of very large differences in steric solvation requirements for the endo- (globular in shape) and exo- (plate-like in shape) transition states in these reactions, no variation in product ratio with solvent phase is observed in any case.The inability of the ordered liquid crystalline phases to differentiate between endo- and exo-transition states in the Diels–Alder reactions investigated is rationalized as being the possible result of several factors. The most important of these are believed to be free volume effects, owing to both inefficient steric solvation of the bulky diene and volume contraction in the transition states for cycloaddition.



1982 ◽  
Vol 104 (21) ◽  
pp. 5719-5728 ◽  
Author(s):  
Stephen G. Pyne ◽  
Mark J. Hensel ◽  
P. L. Fuchs


1980 ◽  
Vol 102 (18) ◽  
pp. 5960-5962 ◽  
Author(s):  
Stephen G. Pyne ◽  
Mark J. Hensel ◽  
Stephen R. Byrn ◽  
Ann T. McKenzie ◽  
P. L. Fuchs




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