title: Oxazoline-based organocatalyst for enantioselective strecker reactions: a protocol for the synthesis of levamisole.
abstract: A chiral oxazoline-based organocatalyst has been found to efficiently catalyze asymmetric Strecker reactions of various aromatic and aliphatic N-benzhydrylimines with trimethylsilyl cyanide (TMSCN) as a cyanide source at -20 °C to give α-aminonitriles in high yield (96 %) with excellent chiral induction (up to 98 % ee). DFT calculations have been performed to rationalize the enantioselective formation of the product with the organocatalyst in these reactions. The organocatalyst has been characterized by single-crystal X-ray diffraction analysis, as well as by other analytical methods. This protocol has been extended to the synthesis of the pharmaceutically important drug molecule levamisole in high yield and with high enantioselectivity.
authors.affiliation: Discipline of Inorganic Materials and Catalysis, Central Salt & Marine Chemicals Research Institute (CSIR-CSMCRI), G.B. Marg, Bhavnagar, 364002 (India).
authors.forename: Arghya
authors.initials: A
authors.lastname: Sadhukhan
authors.forename: Debashis
authors.initials: D
authors.lastname: Sahu
authors.forename: Bishwajit
authors.initials: B
authors.lastname: Ganguly
authors.forename: Noor-ul H
authors.initials: NU
authors.lastname: Khan
authors.forename: Rukhsana I
authors.initials: RI
authors.lastname: Kureshy
authors.forename: Sayed H R
authors.initials: SH
authors.lastname: Abdi
authors.forename: E
authors.initials: E
authors.lastname: Suresh
authors.forename: Hari C
authors.initials: HC
authors.lastname: Bajaj
mesh_terms: D001559:Benzhydryl Compounds / Q000737:chemistry*; D002384:Catalysis; D003486:Cyanides / Q000737:chemistry*; D007097:Imines / Q000737:chemistry*; D007978:Levamisole / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D009570:Nitriles / Q000737:chemistry*; D010080:Oxazoles / Q000737:chemistry*; D011789:Quantum Theory; D013237:Stereoisomerism; D014297:Trimethylsilyl Compounds / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D001559:Benzhydryl Compounds; D003486:Cyanides; D007097:Imines; D009570:Nitriles; D010080:Oxazoles; D014297:Trimethylsilyl Compounds; D007978:Levamisole; C058010:trimethylsilyl cyanide
keywords: Strecker reaction; aminonitriles; enantioselectivity; organocatalysis; oxazoline