Imidazolium ion tethered TsDPENs as efficient ligands for Iridium catalyzed asymmetric transfer hydrogenation of α-keto phosphonates in water

• Published in: Journal of organometallic chemistry Vol. 810; pp. 12 - 14
• Main Authors: Sun, Mengxia, Campbell, Joann, Kang, Guowei, Wang, Huigang, Ni, Bukuo
• Format: Journal Article
• Language: English
• Published: LAUSANNE Elsevier B.V 15.05.2016; Elsevier
• Subjects: Asymmetric transfer hydrogenation; Chemistry; Chemistry, Inorganic & Nuclear; Chemistry, Organic; Iridium; Physical Sciences; Science & Technology; Water; α-Ketophosphonates; Water; α-Ketophosphonates; Iridium; Asymmetric transfer hydrogenation; GREENER; ACIDS; HYDROXYPHOSPHONATES; ALDEHYDES; MICHAEL ADDITION; BETA; REDUCTION; KETOPHOSPHONATES; alpha-Ketophosphonates; HIGHLY ENANTIOSELECTIVE HYDROPHOSPHONYLATION
• ISSN: 0022-328X; 1872-8561
• DOI: 10.1016/j.jorganchem.2016.03.010

For the first time, an efficient method has been developed by the use of imidazolium ion tethered TsDPENs as efficient ligands for Iridium-catalyzed asymmetric transfer hydrogenation (ATH) of α-ketophosphonates in water. The reaction provided the desired product α-hydroxyphosphonates in moderate to good yields (44–78%) and good to excellent enantioselectivities (up to >99% ee) under mild reaction conditions without adding any surfactants. The enantiomeric excess was determined by 13P NMR by using (−)-cinchonidine as chiral solvating agent, which is a much more convenient method than chiral HPLC. Asymmetric transfer hydrogenation (ATH) of α-ketophosphonates in water using imidazolium ion tethered TsDPENs ligands in high to excellent enantioselectivities. [Display omitted] •Imidazolium ion tethered TsDPENs were used as efficient ligands for ATH of α-ketophosphonates in water.•The products of α-hydroxyphosphonates were obtained in good to excellent enantioselectivity.•The reactions can be conducted under mild conditions with low loading of both catalyst and hydride donor HCO2Na.