Solvolyse von Toluolsulfonsäureestern, XX. Methanolyse der Tosylate von cis‐ und trans‐1‐Isopropyl‐cyclopentanol‐(2) sowie von 2t.9c.10c‐Decalol

Solvolytic El eliminations from cis-alkylated p-toluenesulfonates of cycloalkanols (particularly menthols and decalols) lead almost exclusively to "Saytzeff hydrocarbons" ; this fact is accounted for by the increase in the rate of solvolysis that results from the participation of the tertiary trans-hydrogen. The corresponding trans-alkylated compounds give mixtures. The solvolysis of these compounds is compared with the deamination of stereoisomeric primary amines and with the proton-catalysed dehydration of tertiary alcohols. E2 reaction of vicinally alkylated cycloalkane derivatives involves attack on the secondary hydrogen, and in the case of the trans isomers leads to pure "Hofmann hydrocarbon"; with the cis-isomers, competition occurs between the El and E2 reactions. The fact that the tertiary hydrogen is not attacked is explained by its anionic character. Reference is made to the competition of E l and E2 reactions in exhaustive methylation. IntroductionThe first article dealing with the solvolysis of p-toluenesulfonates and chlorides of the menthol and decalol series [I] contained important information (from the preparative point of view) on the relationship between substitution and elimination processes, and it was recognized that El reactions and E2 reactions lead to fundamentally different results. Observations on this topic are scattered throughout the literature, with the result that many have been overlooked by various authors and their general significance has not been appreciated. The present review i s an attempt to correct this situation.All systematic investigations on El and E2 reactions have been based on comparison of the two contradictory elimination rules propounded by Saytzef [z] and by Hofmann[31. According to these rules, the course of elimination depends on the number of hydrogen atoms on the neighboring atoms.The Saytzeff rule states that hydrogen is eliminated from the neighboring atom carrying the smallest number of hydrogen atoms, while according to the Hofmann rule elimination takes place from the neigh- 191 (1940).[2] A . M . Suytzef, Liebigs Ann. Chem. 179, 296 (1875). 131 A. W. Hofmann, Ann. Chem. Pharm. 78, 253 (1851); 79, 11 (1851). boring atom with the largest number of hydrogen atomS [2,3,3al. Other workers have tried to find a theoretical interpretation of this. We, on the other hand, have started by merely noting which of the two rules is obeyed. In certain cases it has been possible to gain an insight into the underlying principles on the basis of the reaction mechanism.We have restricted our investigations to experiments with alicyclic compounds of known configuration and, in most cases, known conformation. The preferred carbon skeleton is the saturated cyclohexane ring, particularly in the menthane and decalin series. The standard substituents are an esterified hydroxyl group in the solvolysis experiments and an amino group in the deamination and exhaustive methylation experiments. The substituent is always situated on a secondary carbon atom, and may be elim...

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Solvolyse von Toluolsulfonsäureestern, XX. Methanolyse der Tosylate von cis‐ und trans‐1‐Isopropyl‐cyclopentanol‐(2) sowie von 2^t.9^c.10^c‐Decalol

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Syntheses and eliminations of cyclopentyl derivatives

Syntheses and eliminations of cyclopentyl derivatives

Über Abspaltungsreaktionen cyclischer cis‐trans‐Isomerer

Eliminations in Cyclic cis‐trans‐Isomers

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