1490-14-8Relevant academic research and scientific papers
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.
supporting information, p. 13703 - 13708 (2021/09/09)
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.
Carbene-catalyzed enal γ-carbon addition to α-ketophosphonates for enantioselective access to bioactive 2-pyranylphosphonates
Sun, Jun,He, Fangcheng,Wang, Zhongyao,Pan, Dingwu,Zheng, Pengcheng,Mou, Chengli,Jin, Zhichao,Chi, Yonggui Robin
supporting information, p. 6040 - 6043 (2018/06/18)
A carbene-catalyzed enantioselective [4+2] cycloaddition reaction between α,β-unsaturated aldehydes and α-ketophosphonates is developed. The reaction affords chiral 2-pyranylphosphonates with excellent enantioselectivities. The optically enriched phosphonate products bear multiple functional groups, including unsaturated lactone and phosphonate moieties that often lead to unique bio-activities. Preliminary studies show that the products from our reactions exhibit anti-bacterial (X. oryzae pv. oryzae) and anti-viral (Tobacco Mosaic Virus) activities for potential use in plant protection.
Enantioselective synthesis of quaternary α-aminophosphonates via conjugate addition of α-nitrophosphonates to enones
Bera, Kalisankar,Namboothiri, Irishi N. N.
supporting information; experimental part, p. 980 - 983 (2012/04/04)
Enantioselective Michael addition of α-nitrophosphonates to enones for the synthesis of α-aminophosphonates is reported for the first time. The reaction proceeds in good to high yields and moderate to high selectivity in the presence of a new quinine thio
Catalytic asymmetric claisen rearrangement of enolphosphonates: Construction of vicinal tertiary and all-carbon quaternary centers
Tan, Jiajing,Cheon, Cheol-Hong,Yamamoto, Hisashi
supporting information; experimental part, p. 8264 - 8267 (2012/09/08)
A copper-catalyzed enantioselective Claisen rearrangement of easily accessible enolphosphonates using the commercially available PhBOX as the chiral ligand was developed. A wide range of rearrangement products with contiguous tertiary and all-carbon quaternary centers were obtained in excellent yields and stereoselectivities. The α-ketophosphonate substituent in the products could be easily transformed into other functional groups. Copyright
Nicotinium dichromate (= 3-carboxypyridinium dichromate; NDC) as an efficient reagent for the oxidative deamination of amines and aminophosphonates
Sobhani, Sara,Aryanejad, Sima,Maleki, Mahdi Faal
experimental part, p. 613 - 617 (2012/05/20)
A new method for the efficient synthesis of aldehydes, ketones, and oxophosphonates from various types of amines (primary and secondary) and aminophosphonates via oxidative deamination by nicotinium dichromate (= 3-carboxypyridinium dichromate; NDC) is described.
