Reaction of alpha-oximinophosphonates first with acetic anhydride then with iron powder and acetic acid at 50-60 degreesC results in the clean formation of an E-Z mixture of alpha-phosphonoenacetamides. which are immediate precursors to alpha-ammophosphonic acids. (C) 2002 Elsevier Science B.V. All rights reserved.
Highly Enantioselective Synthesis of α-Hydroxy Phosphonic Acid Derivatives by Rh-Catalyzed Asymmetric Hydrogenation with Phosphine–Phosphoramidite Ligands
Organocatalyzed asymmetric Michael reaction of β-aryl-α-ketophosphonates and nitroalkenes
作者:Jie Guang、John Cong-Gui Zhao
DOI:10.1016/j.tetlet.2013.08.015
日期:2013.10
The first enantioselective Michael reaction of beta-aryl-alpha-ketophosphonates and nitroalkenes has been realized by using a new bifunctional Takemoto-type thiourea catalyst. The primary Michael adducts obtained were converted in situ to the corresponding amides through the aminolysis. High yields, excellent diaste-reoselectivities (>95:5 dr), and good enantioselectivities (up to 81% ee) have been achieved for the corresponding oc,13-disubstituted gamma-nitroamides. This reaction again demonstrated that alpha-ketophosphonates are interesting pronucleophiles that can be used as amide surrogates in organocatalyzed reactions. (C) 2013 Elsevier Ltd. All rights reserved.