Aryl H-phosphonates. 7. Studies on the formation of phosphorus-carbon bond in the reaction of trityl and benzyl halides with dialkyl and diphenyl H-phosphonates
摘要:
The reactions of H-phosphonate diesters with trityl and benzyl halides were investigated using P-31 NMR spectroscopy. It was found that extensive oxidation, which usually accompanies the formation of trityl- or p-nitrobenzylphosphonates from the corresponding alkyl bromides in the Michaelis-Becker reaction, can be considerably suppressed or completely eliminated by reacting p-nitrobenzyl or trityl bromides with diphenyl H-phosphonate in acetonitrile in the presence of DBU. (C) 1997 Elsevier Science Ltd.
Reinvestigation of the 31P NMR evidence for the formation of diorganyl phosphoropyridinium intermediates
作者:Johan Nilsson、Adam Kraszewski、Jacek Stawinski
DOI:10.1039/b107792a
日期:2001.11.29
A 31P NMR study on the reactions of diphenyl and diethyl chlorophosphates/bromophosphates with pyridine showed that equilibria of these reactions are heavily shifted to the left and thus concentrations of the putative diorganyl phosphoropyridinium chlorides/bromides are usually below the detection level of this spectroscopic method. However, when diphenyl iodophosphate was subjected to reaction with pyridine, we were able for the first time to observe the formation of a diorganyl phosphoropyridinium intermediate by 31P NMR spectroscopy.
The reaction of diphenyl and dialkyl phosphorochloridates with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). Formation of phosphonate diesters via N→C phosphorus migration
作者:Annika Kers、Inger Kers、Jacek Stawinski
DOI:10.1039/a904502c
日期:——
Diphenyl and neopentylene phosphorochloridates react with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in acetonitrile to form amidine adducts 3 or 10. These undergo further conversion into the corresponding alkene aminals, followed by probable NâC phosphorus migration to produce stable 6-substituted phosphinoyl derivatives of DBU, 6 or 12, respectively. Diethyl phosphorohalidates (chloride and bromide) also form amidine adduct 13 with DBU, but this does not undergo NâC phosphorus migration.