title: Synthesis of enantiomerically enriched indolines and tetrahydroisoquinolines from (S)-amino acid-derived chiral carbocations: an easy access to (3S,4R)-demethoxy-3-isopropyl diclofensine.
abstract: Enantiomerically enriched indolines and tetrahydroisoquinolines were synthesized within 5 min to 2 h in high yields from easily accessible (S)-amino acid derived chiral carbocations. The diastereoselective Friedel-Crafts reaction is promoted by a Lewis acid (AlCl3) offering trans-diastereoselectivity. The rate of the reaction and diastereoselectivity of the product are significantly influenced by steric hindrance of the amino acids substituents and aryl groups. The methodology can be applied for the synthesis of the enantiomerically enriched bioactive scaffold (3S,4R)-demethoxy-3-isopropyl diclofensine.
authors.affiliation: Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, BS 10/1, Jankipuram Extension, Sitapur Road, Lucknow 226031, India. gautam.panda@gmail.com gautam_panda@cdri.res.in.
authors.forename: Sudipta Kumar
authors.initials: SK
authors.lastname: Manna
authors.forename: Gautam
authors.initials: G
authors.lastname: Panda
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D007211:Indoles / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D013237:Stereoisomerism; D044005:Tetrahydroisoquinolines / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000596:Amino Acids; D007211:Indoles; D044005:Tetrahydroisoquinolines; C057812:indoline