In saturated heterocycles

Many studies have been made of substituent effects in saturated heterocyclic six-membered rings. For a detailed discussion the review of Eliel and Pietrusziewicz should be consulted [Pg.15]

Finegold, H. Nuclear Magnetic Resonance Studies of Weak Intermolecular Forces -Medium Effects in Saturated Heterocyclic Rings. J. Phys. Chem. 72, 3244 (1968). 

Since Eliel and Pietrusiewicz (142) have published a comprehensive review on l3C chemical shifts in saturated heterocycles, the discussion in the present report may be confined to a few basic features for the sake of completeness. It stands to reason that there is an electronegativity dependence of a-carbon chemical shifts. This was demonstrated by Lambert and co-workers (143) for a great variety of pentamethylene heterocycles, and holds also for positively charged species, such as X = (CH3)2N+, (CH3)2P+, CH3S +, Br+, and I+. The same is suggested by the good correlation of a-carbon chemical shifts in some heterocyclohexanes (143) and the a-SCS values in cyclohexanes with equatorial substituents (Figure 2)(114). 

B-78MI50900 B. J. Walker in Saturated Heterocyclic Chemistry , ed. G. Pattenden The... 

Five- and Six-membered Rings and Related Fused Systems , F. G. Riddell, in Saturated Heterocyclic Chemistry , ed. W. Parker, Royal Society of Chemistry, London, 1974, vol. 2, pp. 167-272. 

Conformational Analysis in Saturated Heterocyclic Compounds E. L. Eliel, Acc. Chem. Res., 1970, 3, 1-8. 

Intramolecular Interactions in Saturated Heterocycles with Two Heteroatoms I. A. Shlygina and V. Z. Gabdrakipov, Tr. Inst. Khim. Nauk, Akad. Nauk, Kaz. SSR, 1980,53,55-75. 

B-74MI40700 F. G. Riddell in Saturated Heterocyclic Chemistry , The Chemical Society,... 

M. Jackman and F. A. Cotton Academic Press, New York, 1975, p. 185. B-75MI40800 A. E. A. Porter in Saturated Heterocyclic Chemistry , The Chemical Society,... 

Anomeric Effect in Saturated Heterocyclic Ring Systems... 

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