173848-00-5Relevant articles and documents
Diazophosphonates: Effective Surrogates for Diazoalkanes in Pyrazole Synthesis
Green, Michael T.,Hayes, Christopher J.,Inman, Martyn,Lewis, William,Moody, Christopher J.,Nicolle, Simon M.,Ruffell, Katie,Smith, Frances R.
, p. 13703 - 13708 (2021)
Diazophosphonates, readily prepared from α-ketophosphonates by oxidation of the corresponding hydrazones in batch or in flow, are useful partners in 1,3-dipolar cycloaddition reactions to alkynes to give N-H pyrazoles, including the first intramolecular examples of such a process. The phosphoryl group imbues a number of desirable properties into the diazo 1,3-dipole. The electron-withdrawing nature of the phosphoryl stabilizes the diazo compound making it easier to handle, whilst the ability of the phosphoryl group to migrate readily in a [1,5]-sigmatropic rearrangement enables its transfer from C to N to aromatize the initial cycloadduct, and hence its facile removal from the final pyrazole product. Overall, the diazophosphonate acts as a surrogate for the much less stable diazoalkane in cycloadditions, with the phosphoryl group playing a vital, but traceless, role. The cycloaddition proceeds more readily with alkynes bearing electron-withdrawing groups, and is regiospecific with asymmetrical alkynes. The potential of diazophosphonates for use in bioorthogonal cycloadditions is demonstrated by their facile addition to strained alkynes.
STUDIES ON ORGANOPHOSPHORUS COMPOUNDS. 94. SYNTHESES OF 1-HYDRAZINO- AND 2-HYDRAZINO-ALKYLPHOSPHONIC ACIDS AND DERIVATIVES THEREOF
Yuan, Chengye,Chen, Shoujun,Xie, Rongyuan,Feng, Hanzhen,Maier, Ludwig
, p. 115 - 124 (2007/10/03)
A series of 1-hydrazino- and 2-hydrazino-alkyl (aryl) phosphonic acids and their derivatives were prepared from the corresponding hydrazono compounds by treatment with sodium cyanoborohydride or with the borane-tetrahydrofuran complex, respectively. - Key words: Hydrazino-, hydrazono-alkylphosphonates; sodium cyanoborohydride; borane-tetrahydrofuran complex
