- Synthesis of PO(OR)2- and PR3+-disubstituted pyridines via N- (trifluoromethylsulfonyl)pyridinium triflates
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The efficient synthesis of dialkoxyphophoryl- and phosphonio-substituted pyridines is reported. The cationic heterocycle of N- (trifluoromethylsulfonyl)pyridinium triflate (3), or of analogous N- (trifluoromethylsulfonyl) compounds prepared from pyridine-4-phosphonium salts 5, turns out to be sufficiently activated to allow attack of P(OR)3 and PR3 nucleophiles to give the novel compounds bis(dialkoxyphosphoryl)pyridines 11 phosphonio(dialkoxyphosphoryl)pyridines 13. For example, 13a-d, with PO(OR)2 at the C2 and PR3+ at the C4 position, represent the first examples of an N-heteroaromatic ring substituted by both dialkoxyphosphoryl and phosphonio moieties. The structure of 13b [PPh3+/PO(O-i-Pr)2] was confirmed by X-ray analysis. In most cases, the intermediate 1-(trifluoromethylsulfonyl)dihydropyridines, such as 7, 8 (monosubstituted) or 10a and b and 12a-d (disubstituted), are sufficiently stable for isolation.
- Haase, Mirko,Goerls, Helmar,Anders, Ernst
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- Pd-catalyzed C–P coupling of heteroaryl boronic acid with H-phosphonate diester
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We report herein a novel protocol to construct C–P bond from heteroaryl boronic acid with H-phosphonate diester under Pd–Ag catalyzed system without addition of base. This method, directly using commercial available heteroaryl boronic acid as the starting
- Geng, Zhiyue,Zhang, Yudan,Zheng, Lu,Li, Jingya,Zou, Dapeng,Wu, Yangjie,Wu, Yusheng
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supporting information
p. 3063 - 3066
(2016/07/06)
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- Revisiting the Hirao cross-coupling: improved synthesis of aryl and heteroaryl phosphonates
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The palladium-catalyzed cross-coupling of dialkylphosphite with aromatic electrophiles (Hirao coupling) was re-investigated. Some limitations in terms of palladium loadings and substrate reactivity are alleviated with the use of Pd(OAc)2 comple
- Belabassi, Yamina,Alzghari, Saeed,Montchamp, Jean-Luc
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p. 3171 - 3178
(2008/12/22)
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- Preparation of pyridyl-4-phosphonates
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This invention relates to the preparation of pyridyl-4-phosphonates by reacting phosphite ester salts with pyridines which are N-substituted with sterically hindering or "bulky" groups such as "bulky" phenyl groups, for example trityl, φ3 C-.
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