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Carbon‐13 Nuclear Magnetic Resonance Spectroscopic Analyses of 3‐Aryl‐3‐hydroxyl‐2,2,4,4‐tetramethylcyclobutanones and Related Compounds
Author(s) -
Lin ShawTao,
Lin WenChung,
Yeh YuenHan
Publication year - 2000
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.200000034
Subject(s) - chemistry , aryl , chemical shift , substituent , ring (chemistry) , polar , stereochemistry , resonance (particle physics) , medicinal chemistry , crystallography , nuclear magnetic resonance , organic chemistry , alkyl , physics , particle physics , astronomy
A series of 2‐aryl‐2‐hydroxy‐1,1,3,3‐tetramethyl‐5,8‐dioxaspiro[3.4]octanes ( 1 ), 3‐aryl‐3‐hydyoxyl‐2,2,4,4‐tetyramethylcyclobutanones ( 2 ), and l‐aryl‐2,2,4‐trimethyl‐1,3‐pentadiones ( 3 ) were studied using 13 C NMR analyses. The chemical shifts of C‐c are dependent on the substituent groups on the phenyl ring for compounds 1 (ρ =‐0.966, R 2 = 0.987) and 2 (ρ = −1.378, R 2 = 0.998). The chemical shifts of C‐a follow a similar trend (ρ =−0.926, R 2 = 0.989). In the case of compounds 3 , C‐c yielded the opposite trend with very poor correlation coefficiency (ρ = 1.22, R 2 = 0.179). This result reveals the field effect of a polar bond and resonance‐induced changes in pi electron‐density at C‐1 on the cyclobutanering series.