- Anhydrides of Phosphorus and Sulfur Acids, 2. Mixed Anhydrides of Phosphoric, Phosphonic, and Phosphinic Acids with Sulfonic Acids and Sulfuric Monoimidazolide. New Methods of Synthesis, Novel Structures, Phosphorylating Properties
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New applications of methods leading to anhydrides RR'P(O)OSO2R'' (1) are described: a) Reaction of acids RR'P(O)OH (2) with sulfonic imidazolides. b) Reaction of phosphorus imidazolides 4 with sulfonic acids and sulfonic anhydrides.New methods of synthesis of anhydrides 1 have been developed. c) Reaction of phosphorus acid silyl esters RR'P(O)OSiMe3 (9) with methanesulfonic and trifluoromethanesulfonic anhydrides. d) Reaction of bis(trimethylsilyl) tert-butylphosphonate (10) with methanesulfonic acid leading to tBuP(O)(OSO2Me)2 (11). e) Reaction of stannyl phosphate (EtO)2P(O)OSnMe3 (15) with methanesulfonic anhydride. f) Reaction of phosphorus acid silyl esters 9 with trimethylsilyl trifluoromethanesulfonate.All methods result in high yields and can be adapted to a variety of anhydrides 1 derived from phosphoric, phosphonic, and phosphinic acids on the one hand and methanesulfonic, trifluoromethanesulfonic acids and sulfuric monoimidazolide on the other.Phosphonium intermediates have been demonstrated by low temperature FT 31P NMR spectroscopy for reaction b) and c).The anhydrides 1 are readily converted into imidazolides 4 by the reaction with N-(trimethylsilyl)imidazole which proceeds via two distinct phosphonium intermediates.With neutral and weakly basic nucleophiles, the anhydrides 1 behave as phosphorylating agents.
- Dabkowski, Wojciech,Michalski, Jan,Skrzypczynski, Zbigniew
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p. 1809 - 1824
(2007/10/02)
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- Arbuzov Reaction of Alkyl and Silyl Phosphites with Halogens involving Four- and Five-co-ordinate Intermediates
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Low temperature 31P n.m.r. spectroscopy and chemical data have been applied to elucidate the mechanism of the Arbuzov-type reaction between phosphites and halogens.Simple and substituted trialkyl, alkyl 1,2-phenylene, and trisilyl phosphites have been allowed to react with chlorine, bromine, and iodine.In some cases intermediate halogenophosphonium salt (2) and in others halogenophosphoranes (3) are observed which then decompose into the corresponding pure highly reactive phosphorohalidates (4).It was possible to prepare stable phosphonium salts from halogenophosphonium salts (2) and halogenophosphoranes (3).
- Michalski, Jan,Pakulski, Marek,Skowronska, Aleksandra
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p. 833 - 836
(2007/10/02)
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