Composes du phosphore dicoordonne: Reaction de diaza-1,4 dienes-1,3 disubstitues sur les derives de diazaphosphole. Du triazaphosphole-1,2,4,3 et de precurseurs de composes du phosphore dicoordonne

Cycloaddition reactions of heterophospholes

“…The latter course is observed, particularly in those cases, where a nitrogen lone pair is conjugated to the ❍ ❍ ✟ ✟C P bond. cloadducts with ␣-diimines [18] and benzil [21]. Similar reactions are given by AlCl 3 -complexed 1-phenyl-1,3,2-benzodiazaphosphole [87] and 1,3,2-benzoxazaphosphole [18] with ␣-diimines.…”

“…cloadducts with ␣-diimines [18] and benzil [21]. Similar reactions are given by AlCl 3 -complexed 1-phenyl-1,3,2-benzodiazaphosphole [87] and 1,3,2-benzoxazaphosphole [18] with ␣-diimines. A cyclohexane anellated 1,2,3-diazaphosphole reacts analogously [79].…”

“…2-Methyl-5-phenyl-1,2,4,3-triazaphosphole 10 forms a stable [1 + 4] cycloadduct 81 with ␣-diimines [18,88,89], but the [1 + 4] cycloadduct produced with ␣-diketone dimerizes to give a diazadiphosphetidine derivative 82 having fivecoordinate phosphorus [21]. Likewise, reaction with azodicarboxylic esters leads to 83 via [1 + 4] cycloaddition followed by dimerization [22] (Scheme 25).…”

Recent Developments in the Chemistry of N-Heterocyclic Phosphines

“…Explanation for this -at first glance illogical -finding is feasible if one considers that aromatic 1,3,2-diazaphospholenium cations, although being intrinsically weaker electrophiles, still have a larger charge capacity than non-aromatic diaminophosphenium ions and are thus able to accept higher overall charge transfer from a p -basic metal fragment; furthermore, subtle inductive substituent effects may also play a role. Neutral benzo-1,3,2-diazaphospholes or their tetrameric cycloaddition products react with hard Lewis acids to give N-coordinated Lewis acid-base complexes [13,80,81] ; this reaction can be used to disassemble the otherwise stable oligomers into monomeric units at ambient temperature.…”

1,3-Dipolar cycloadditions of 9-diazofluorenes and diphenyldiazomethane to 2-acyl-2H-1,2,3-diazaphospholes

“…HOMO and the next HOMO) [9], whereas benzoxaphospholes, for instance, have a 10 -delocalized ring system with all the three highest occupied MOs being -orbitals [10]. On the other hand, the P atom of anellated heterophospholes with high -electron density tend to act as a [1+4]cheletropic center and react with heterodienes such as -diketones and -diimines to give the spirocyclic adducts [11,12].…”