4141-49-5Relevant articles and documents
Preparation method of large-steric-hindrance alkyl substituted phosphite diester
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Paragraph 0152-0155, (2020/04/06)
The invention discloses a preparation method of large-steric-hindrance alkyl substituted phosphite diester, and relates to a novel method for preparing the large-steric-hindrance alkyl substituted phosphite diester compound which is difficult to synthesiz
Phosphorus Compounds with Unusual Coordination, 3. Comparison of the Cycloaddition Behaviour of Diphenylketene and Triphenylphosphene
Regitz, Manfred,Urgast, Klaus,Maas, Gerhard
, p. 67 - 76 (2007/10/02)
Triphenylphosphene (3b), generated thermally or photochemically from 1b, undergoes olefination reaction with 4,5-benzotropone (6) to yield 1-(diphenylmethylen)-4,5-benzocycloheptatriene (9); the oxaphosphetane 7b is assumed to be the intermediate of this reaction.In an analogous way, 4-pyrone (15) is transformed into 4-(diphenylmethylen)pyrane (16).Corresponding olefination behaviour is observed in the reactions of 6 and 15 with diphenylketene.In the reaction of tetracyclone (20) with diphenylketene (3a), the olefination sequence leads to the formation of (diphenylmethylen) tetraphenylcyclopentadiene (21) via betain 22a and the cycloadduct 23a.The spirocyclic reaction product 26a probably arises from the same betain - like intermediate (22a *** 25a *** 26a).The analogy in triphenylphosphene reactivity towards 20 is restricted to the -cycloaddition step (formation of 26b). - Keywords: Diphenylketene, Triphenylphosphene, Cycloaddition with CO-Compounds, Crystal Structure
Equilibrium CH-acidity of organophosphorus compounds - Communication 1. Influence of the solvent on the CH-acidity of phosphine oxides and phosphine sulfides
Mesyats,Tsvetkov,Petrov,Terekhova,Shatenshtein,Kabachnik
, p. 2399 - 2405 (2007/10/10)
1. The equilibrium CH-acidity (pK) of phosphine oxides and phosphine sulfides of analogous structure was determined in diglyme (DG) and in DMSO by the method of transmetallation. The acidity of the phosphine sulfides is almost unchanged from one solvent to another. The acidity of phosphine oxides in relatively nonpolar DG is three to five orders of magnitude higher than in DMSO, on account of the coordination of the phosphoryl group of the carbanions with the alkali metal cation in DG. The ionic dissociation constants of Li-substituted phosphine oxides in DG are two to three orders of magnitude lower than for phosphine sulfides. The distance between ions in ion pairs in Li-substituted phosphine oxides is reduced. 2. For an estimation of the acidifying effect of phosphinyl and thiophosphinyl groups, we used the pK in DMSO. Thiophosphinyl substituents negligibly exceed phosphinyl groups in their summary acidifying effect. 3. The introduction of (C6H5)2PO and (C6H5)2PS groups as substituants into diphenylmethane and fluorene increases the acidity of the latter by ～8 units of pK.
