title: Organocatalyzed asymmetric Michael addition by an efficient bifunctional carbohydrate-thiourea hybrid with mechanistic DFT analysis.
abstract: A series of thiourea based bifunctional organocatalysts having d-glucose as a core scaffold were synthesized and examined as catalysts for the asymmetric Michael addition reaction of aryl/alkyl trans-β-nitrostyrenes over cyclohexanone and other Michael donors having active methylene. Excellent enantioselectivities (<95%), diastereoselectivities (<99%), and yields (<99%) were attained under solvent free conditions using 10 mol% of 1d0. The obtained results were explained through DFT calculations using the B3LYP/6-311G(d,p)//B3LYP/6-31G(d) basic set. The QM/MM calculations revealed the role of cyclohexanone as a solvent as well as reactant in the rate determining step imparting 31.91 kcal mol-1of energy towards the product formation.
authors.affiliation: "Hygeia" Centre of Excellence in Pharmaceutical Sciences (CEPS), GGS Indraprastha University, Sec. 16-C, Dwarka, New Delhi, 110078, India. aknarula58@gmail.com.
authors.forename: Chandra S
authors.initials: CS
authors.lastname: Azad
authors.forename: Imran A
authors.initials: IA
authors.lastname: Khan
authors.forename: Anudeep K
authors.initials: AK
authors.lastname: Narula
mesh_terms: D000475:Alkenes / Q000138:chemical synthesis* / Q000737:chemistry; D000588:Amines / Q000737:chemistry; D002241:Carbohydrates / Q000737:chemistry*; D002384:Catalysis; D003512:Cyclohexanones / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D009574:Nitro Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D011789:Quantum Theory; D013237:Stereoisomerism; D013890:Thiourea / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D000475:Alkenes; D000588:Amines; D002241:Carbohydrates; D003512:Cyclohexanones; D009574:Nitro Compounds; C036468:cyclohexanone; D013890:Thiourea