Aggregation and Alkylation of Enolates of 2-Phenyl--tetralone and 2,6-Diphenyl-
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- 作者：Daniel Zerong Wang ; Yeong-Joon Kim ; and Andrew Streitwieser
- 刊名：Journal of the American Chemical Society
- 出版年：2000
- 出版时间：November 8, 2000
- 年：2000
- 卷：122
- 期：44
- 页码：10754 - 10760
- 全文大小：104K
- 年卷期：v.122,no.44(November 8, 2000)
- ISSN：1520-5126
文摘
The cesium (1-Cs, CsPhPAT) and lithium (1-Li, LiPhPAT) enolates of 2,6-diphenyl-
-tetralone,1, and the lithium enolate (2-Li, LiPhAT) of 2-phenyl--tetralone, 2, are present in dilute THF solution asmonomers and dimers with K1,2 = 1810 (1-Cs, CsPhPAT), 2650 (1-Li, LiPhPAT), and 1930 (2-Li, LiPhAT)M-1. These values were obtained by singular value decomposition analysis of the UV spectra and by thedependence of ion pair pK's with concentration. On the ion pair pK scales previously defined, the monomershave pK = 17.80 (1-Cs, CsPhPAT) and 11.14 (1-Li, LiPhPAT). The monomers are much faster than dimersin alkylation reactions; reaction products from alkyl halides are those of C-alkylation, but 1-Cs (CsPhPAT)with methyl sulfonates gives large amounts of O-alkylation. Comparison with previous results shows that thereactivity of cesium enolates parallels their basicity but that lithium enolates show no correlation between ionpair pK and alkylation reactivity.
-tetralone,1, and the lithium enolate (2-Li, LiPhAT) of 2-phenyl--tetralone, 2, are present in dilute THF solution asmonomers and dimers with K1,2 = 1810 (1-Cs, CsPhPAT), 2650 (1-Li, LiPhPAT), and 1930 (2-Li, LiPhAT)M-1. These values were obtained by singular value decomposition analysis of the UV spectra and by thedependence of ion pair pK's with concentration. On the ion pair pK scales previously defined, the monomershave pK = 17.80 (1-Cs, CsPhPAT) and 11.14 (1-Li, LiPhPAT). The monomers are much faster than dimersin alkylation reactions; reaction products from alkyl halides are those of C-alkylation, but 1-Cs (CsPhPAT)with methyl sulfonates gives large amounts of O-alkylation. Comparison with previous results shows that thereactivity of cesium enolates parallels their basicity but that lithium enolates show no correlation between ionpair pK and alkylation reactivity.