Asymmetric Synthesis of α‐Amino Phosphonic Acids using Stable Imino Phosphonate as a Universal Precursor. Issue 60 (20th September 2019)

• Record Type: Journal Article
• Authors: Inokuma, Tsubasa; Sakakibara, Takuya; Someno, Takatoshi; Masui, Kana; Shigenaga, Akira; Otaka, Akira; Yamada, Ken‐ichi
• Is Part Of: Chemistry. Volume 25:Issue 60(2019)
• Page Start: 13829
• Page End: 13832
• Publication Date: 2019-09-20
• Subjects: amino phosphonic acids -- asymmetric catalysis -- enantioselectivity -- imino phosphonates -- organocatalysis; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201903572
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: A practical method for synthesizing chiral α‐amino phosphonic acid derivatives was developed. Readily available and stable N‐o ‐nitrophenylsulfenyl (Nps) imino phosphonate was utilized as a substrate for a highly enantioselective Friedel–Crafts‐type addition of indole or pyrrole nucleophiles catalyzed by chiral phosphoric acid. The resulting adduct was easily converted into N ‐9‐fluorenylmethyloxycarbonyl (Fmoc) amino phosphonic acid, which is useful for synthesizing peptides containing an amino phosphonic acid. Abstract : Stable imino phosphonate : Enantioselective Friedel–Crafts‐type reaction of imino phosphonate and indoles or pyrroles has been achieved (see scheme). The readily available and stable N ‐2‐nitrophenylsulfenyl (Nps) imino phosphonate can be used as a universal substrate, and the protective groups of the adducts (Nps and Bn) could be readily removed to generate biologically important α‐amino phosphonic acid derivatives.