Synthesis of nitro- and aminoalkylphosphonates

Asymmetric Synthesis ofα-Substitutedβ-Nitrophosphonic Acids by Phospha-Analogous Michael Addition to Aromatic Nitroalkenes

“…[6] Similarly, in a number of titanium ± phosphane complexes [Ti (2,4-C 7 H 11 ) 2 PX 3 ], TiÀP bond lengths and dissociation energies were found experimentally to decrease along the series X CH 3 , OC 2 H 5 , F. [7] In contrast, in some polyfluorinated hydrocarbons, C À C bond lengths and dissociation energies apparently increase with increasing fluorine substitution. [8] There is clearly a need for systematic studies aimed at elucidating under which circumstances and in which direction deviations from the usual correlations may be expected. Here we report a high-level ab initio case study on the SnÀSn bond lengths, homolytical dissociation energies, and force constants in distannane, Sn 2 H 6 , and several of its fluorine-substituted derivatives.…”

“…Here we report a high-level ab initio case study on the SnÀSn bond lengths, homolytical dissociation energies, and force constants in distannane, Sn 2 H 6 , and several of its fluorine-substituted derivatives. This particular choice of model systems has several advantages: 1) a homonuclear bond is studied, and thus polar bonding contributions may be minimized or, for symmetrical substitution, eliminated; 2) in contrast to firstrow compounds, [8] complicating effects of negative hyperconjugation are expected to be minor for the properties discussed; 3) the systems are still sufficiently small to obtain definite results from highly accurate coupled-cluster calculations with extended basis sets. [9] Table 1 provides computed SnÀSn bond lengths, dissociation energies, and force constants.…”

“…A convenient route to b-aminophosphonic acids is provided by the addition of phosphorus compounds bearing a labile phosphorus À hydrogen bond to nitroalkenes, first developed by Pudovik et al, [7] and the subsequent reduction of the nitro group. [8] However, the addition of dialkylphosphites to aromatic nitroalkenes leads to extensive polymerization of the nitro compounds. Examples of addition of di-and trialkylphosphites to unsaturated nitro compounds were also described by Yoshimura et al, [9] who were able to add diethylphosphite to aliphatic nitroalkenes at 100 8C in moderate yields.…”

Asymmetrische Syntheseα-substituierterβ-Nitrophosphonsäuren durch phospha-analoge Michael-Addition an aromatische Nitroalkene

“…[4] Ihre Wirksamkeit ist auf die ¾hnlichkeit mit den natürlichen a-und b-Aminosäuren und die im Vergleich zu P-O-und Amidbindungen unter hydrolytischen Bedingungen stabilere C-P-Bindung zurückzuführen. Die zuerst von Pudovik et al [7] entwickelte Addition von Phosphorverbindungen, die eine labile Phosphor-Wasserstoff-Bindung enthalten, an Nitroalkene und die folgende Reduktion der Nitrogruppe [8] stellen eine einfache Methode zur Herstellung von b-Aminophosphonsäuren dar. [5] Bislang wenig untersucht worden ist dagegen die asymmetrische Synthese von b-Aminophosphonsäuren [6] und deren Vorstufen.…”

Asymmetric Synthesis of -Substituted -Nitrophosphonic Acids by Phospha-Analogous Michael Addition to Aromatic Nitroalkenes

“…In particular, phosphonates [3] bearing heteroatomic substituents in the a-or bposition to the phosphorus atom have shown strong activities as antibiotics, anticancer drugs, herbicides, and enzyme inhibitors. [8] However, the addition of dialkylphosphites to aromatic nitroalkenes leads to extensive polymerization of the nitro compounds. Optically active a-hydroxy and a-aminophosphonic acids can nowadays be prepared by a variety of methods.…”