Substituenteneinfluss der phosphino- und der phosphinylgruppe auf die reaktivität aromatischer verbindungen—I

Substituent effects of phosphorus-containing groups on aromatic reactivity. Determination of substituent constants by 13C nuclear magnetic resonance spectroscopy

“…This should result in total electronic effects for these substituents upon reactivity which are weak in magnitude and possibly variable in direction, depending on the relative response of the reaction center to inductive and resonance effects. In reactions studied by Klabuhn et al (6), the PR, (R = cyclohexyl, phenyl) behaves in ester hydrolysis as a weakly electron-withdrawing (by a factor of ca. 2) and in S,1 reaction as a weakly electron-donating (by a factor of ca.…”

“…Substrates 2,3,4,9,10,14,15, and 18 were commercial products and were recrystallized or distilled where necessary. Substrates 1,5,6,7,8,11,12,13,16,and 19 were synthesized according to standard procedures.…”

“…Substituent constants derived by Schindlbauer and Prikoszovich (5) from 1 9~ nmr chemical shifts for a series of meta and para substituted fluorobenzenes clearly show that P(O)Z, is always more electron withdrawing than the corresponding PZ, group. Recently, Klabuhn et al (6) demonstrated that in various reactions (base-catalyzed ester hydrolysis, aromatic nucleophilic substitution, SN2 and SN1 reactions), the p-P(O)R, substituent (R = phenyl, cyclohexyl) is significantly more electron withdrawing than the corresponding p-PR, group; the reactivity ratio varied from 1.6 to 380. Unfortunately, Retcofsky and Griffin's results have recently been uncritically cited by Nelson and Williams in their review article (ref.…”

From rocks to bioactive compounds: a journey through the global P(v) organophosphorus industry and its sustainability

“…Nevertheless, phosphinyl groups are moderately electronwithdrawing by resonance, making them meta director and deactivator in the case of electrophilic aromatic substitutions. 85,86 Alternatively, the strong electron-withdrawing effect of phosphoryl bonds enables them to stabilize carbanions or saturated carbons at the a position. Those properties make the phosphoryl bond a singular one in nature and will explain the bioactivity of many phosphorylated molecules.…”