REACTIONS OF PHOSPHONIC ACID ESTERS WITH NUCLEOPHILES .2. SURVEY OF NUCLEOPHILES REACTING WITH PARA-NITROPHENYL METHYLPHOSPHONATE ANION
REACTIONS OF PHOSPHONIC ACID ESTERS WITH NUCLEOPHILES .2. SURVEY OF NUCLEOPHILES REACTING WITH PARA-NITROPHENYL METHYLPHOSPHONATE ANION
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DOI：
10.1021/jo00834a044
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发表时间：
1970-01-01
影响因子：
3.6
通讯作者：
ISAKS, M
中科院分区：
文献类型：
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作者：
BEHRMAN, EJ;BIALLAS, MJ;ISAKS, M
(48)J. Epstein和WA Mosher，J. Phys. Chem，72，622（1968）及其参考文献，60和（fc2）0 α = 4.2 M-1 min-1，钙离子浓度为0.05 M。因此，对于单阴离子底物，[Ca（H2O）2（OH）]+的反应性比OH-的反应性大约200倍。根据所提供的数据49，钙离子的反应性应略低于镁离子的反应性（基于pKa值），因此，事实上，（&2）µ m/（&2）-的比值可能大于200。基于两种效应，沙林和p-NPMP之间的行为差异是合理的。第一，带正电荷的金属离子应更强烈地吸引到p-NPMP的阴离子比中性沙林。第二，氢氧根离子应该比沙林更难攻击p-NPMP的阴离子。这两种效应都是基于静电因素，都应该增加阳离子催化剂对p-NPMP的相对有效性。
(48) J. Epstein and WA Mosher, J. Phys. Chem,, 72, 622 (1968), and references therein, 60 and (fc2) 0a= 4.2 M~ l min-1 at a calcium ion con-centration of 0.05 M. Thus, with the monoanionic substrate the reactivity of [Ca (H20) zi (OH)]+ is approximately 200 times greater than that of OH-. According to the data presented49 the reactivity of the calcium ion should be somewhat lower than that of the magnesium ion (based on pKa values) so that, in fact, the ratio of (&2) µß/(&2)-could conceivably be greater than 200. The difference in behavior between Sarin and p-NPMP is reasonable on the basis of two effects. First, the positively charged metal ion should be more strongly attracted to the anion of p-NPMP than to the neutral Sarin. Second, hydroxide ion should have more difficulty attacking the anion of p-NPMP than Sarin. Both effects are based on electrostatic factors and both should increase the relative effective-ness of cation catalysis towardp-NPMP.