title: Asymmetric Michael addition of ketones to nitroolefins: pyrrolidinyl-oxazole-carboxamides as new efficient organocatalysts.
abstract: Chiral pyrrolidinyl-oxazole-carboxamides were synthesized and used as efficient new organocatalysts for the asymmetric Michael addition of ketones with nitroalkenes under solvent-free conditions. Gratifyingly, the corresponding Michael adducts were obtained in higher yields (up to 99%) and excellent stereoselectivities (up to >99/1 dr and 99% ee). Transition state models have been proposed to account for the high enantio- and diastereoselectivity of these Michael addition reactions and also the energetics have been investigated using density functional methods. These results support the preferential formation of syn-products by the approach of trans-β-nitrostyrene through the re-face of anti-enamine.
authors.affiliation: Medicinal Chemistry & Pharmacology, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India. ahmedkamal@iict.res.in.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Kamal
authors.forename: Manda
authors.initials: M
authors.lastname: Sathish
authors.forename: Vunnam
authors.initials: V
authors.lastname: Srinivasulu
authors.forename: Jadala
authors.initials: J
authors.lastname: Chetna
authors.forename: Kunta
authors.initials: K
authors.lastname: Chandra Shekar
authors.forename: Shalini
authors.initials: S
authors.lastname: Nekkanti
authors.forename: Yellaiah
authors.initials: Y
authors.lastname: Tangella
authors.forename: Nagula
authors.initials: N
authors.lastname: Shankaraiah
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D000577:Amides / Q000737:chemistry*; D002384:Catalysis; D007659:Ketones / Q000737:chemistry*; D015394:Molecular Structure; D009574:Nitro Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010080:Oxazoles / Q000737:chemistry*; D011759:Pyrrolidines / Q000737:chemistry*; D013343:Styrenes / Q000138:chemical synthesis / Q000737:chemistry
chemical_list: D000475:Alkenes; D000577:Amides; D007659:Ketones; D009574:Nitro Compounds; D010080:Oxazoles; D011759:Pyrrolidines; D013343:Styrenes