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Norbornanes. Part 19. The Inductive Model for Norbornyl Cation Formation
Author(s) -
AltmannSchaffner Eva,
Grob Cyril A.
Publication year - 1987
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19870700105
Subject(s) - 2 norbornyl cation , chemistry , solvolysis , inductive effect , yield (engineering) , leaving group , alcohol , medicinal chemistry , group (periodic table) , stereochemistry , ionization , computational chemistry , organic chemistry , ion , thermodynamics , physics , hydrolysis , catalysis
Two CH 3 groups at C(6) of 2‐ exo ‐ ( 10a ) and 2‐ endo ‐norbornyl p ‐toluenesulfonate 11a lower their solvolysis rates in 80% EtOH by factors of 28 and 16, respectively. A spirocyclopropyl group including C(6), as in 21a and 22a , reduces the rate of exo ‐ and endo ‐ionization by factors of 250 and 8, respectively. The geminally dimethyl‐substituted tosylates 10a and 11a yield the 2‐ exo ‐alcohol 10b , whereas the spirocyclopropyl‐substituted tosylates 21a and 22a furnish rearranged 3‐brendanol 23 . These findings are readily rationalized by the inductive model, according to which norbornyl cation formation is controlled by the inductive effect of dorsal substituents.