α-Aminophosphonate derivatives as nucleophiles in diastereoselective and enantioselective palladium catalysed allylic substitution reactions

A heterogeneous catalyst, SiO2-ZnBr2: An efficient neat access for α-aminophosphonates and antimicrobial activity evaluation

“…IR spectroscopic data were recorded on Alpha FT-IR. 1 H, 13 C and 31 P NMR spectroscopic data were recorded on a BRUKER AV 400 spectrometer, and operated at 400 MHz for 1 H, 100 MHz for 13 C and 161.9 MHz for 31 P in CDCl 3 solvent. Tetramethylsilane (TMS) in 1 H and 13 C NMR, and 85% H 3 PO 4 were used as internal and external standards, respectively.…”

“…These derivatives have received considerable attention since they are elegant peptide mimics of biologically active α-aminoacids, able to function as α-aminocarboxylic acid surrogates 1 and intriguing pharmacological and biological applications. 2 Most mammalian cell containing enzymes can hydrolyze phosphate groups, thus, phosphonates are important, stable and very low toxic unique moieties.…”

Enantioselective Palladium-Catalysed Allylation of 1,5-Dimethylbarbituric Acid

“…The combination of 17 with (Ϫ)-quinine led to an improvement to 11% ee for (ϩ)-ABS (double stereoselection). The phosphane oxazoline ligands 18Ϫ20 [47] [48] induced up to 99% ee in allylations in which the stereogenic center is formed in the allylic system and up to 13% ee in allylations in which the stereogenic center is formed in the nucleophile [49] [50] . In the catalytic allylation of BS with allyl acetate, an enantiomeric excess of only about 1% ee for (ϩ)-ABS was obtained.…”

Phase‐Transfer‐Catalyzed Asymmetric Michael Addition of (Iminomethyl)phosphonates to α,β‐Unsaturated Ketones: Access to α‐Aminophosphonic Acid Derivatives

“…In sharp contrast, the utility of phosphoglycine imine esters [(iminomethyl)phosphonates] for the catalytic asymmetric construction of chiral α‐aminophosphonic acids and derivatives has only received limited attention. In 1995, Williams and co‐workers reported one example of a Pd‐catalyzed asymmetric allylation of diethyl (iminomethyl)phosphonate to give products with 96 % ee and a diastereomeric ratio ( dr ) of 87:13 (Scheme a) . Subsequently, Jászay's group disclosed a catalytic asymmetric Michael addition of (iminomethyl)phosphonates to acrylates and acrylonitrile in the presence of α,α,α,α‐tetraaryl‐1,3‐dioxolane‐4,5‐dimethanol (TADDOL) derivatives and chiral crown ethers to give products with moderate enantioselectivities (Scheme b) .…”

“…In 1995, Williams and co-workers reported one example of a Pd-catalyzed asymmetric allylation of diethyl (iminomethyl)phosphonate to give products with 96 % ee and a diastereomeric ratio (dr) of 87:13 (Scheme 1a). [4] Subsequently, Jászay's group disclosed a catalytic asymmetric Michael addition of (iminomethyl)phosphonates to acrylates and acrylonitrile in the presence of α,α,α,α-tetraaryl-1,3-dioxolane-4,5dimethanol (TADDOL) derivatives and chiral crown ethers to give products with moderate enantioselectivities (Scheme 1b). [5] Scheme 1.…”