- 作者: Shaw-Tao Lin, Wen-Chung Lin and Yuen-Han Yeh
- 中文摘要: 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-tetyramethyl- cyclobutanones (2), and 1-aryl-2,2,4-trimethyl-1,3-pentadiones (3) were studied using 13C NMR analyses. The chemical shifts of C-c are dependent on the substituent groups on the phenyl ring for compounds 1 (r =-0.966, R2 = 0.987) and 2 (r = -1.378, R2 = 0.998). The chemical shifts of C-a follow a similar trend (r =-0.926, R2 = 0.989). In the case of compounds 3, C-c yielded the opposite trend with very poor correlation coefficiency (r = 1.22, R2 = 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 cyclobutane ring series.
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