title: Asymmetric cyclopropanation of conjugated cyanosulfones using a novel cupreine organocatalyst: rapid access to δ(3)-amino acids.
abstract: An organocatalytic asymmetric synthesis of a novel, highly functionalised cyclopropane system furnished with versatile substituents and containing a quaternary centre is described. The process utilises a new bifunctional catalyst based on the cinchona alkaloid framework and the products made using this catalyst were obtained as single diastereoisomers, with very high enantioselectivities (up to 96% ee). We have also demonstrated that these resulting cyclopropanes are very useful synthetic intermediates to interesting products, such as the difficult to access δ(3)-amino acids.
authors.affiliation: School of Chemistry, Food and Pharmacy (SCFP), University of Reading, Whiteknights, Reading, Berks RG6 6AD, UK. a.j.a.cobb@reading.ac.uk.
authors.forename: Lewis S
authors.initials: LS
authors.lastname: Aitken
authors.forename: Lisa E
authors.initials: LE
authors.lastname: Hammond
authors.forename: Rajkumar
authors.initials: R
authors.lastname: Sundaram
authors.forename: Kenneth
authors.initials: K
authors.lastname: Shankland
authors.forename: Geoffrey D
authors.initials: GD
authors.lastname: Brown
authors.forename: Alexander J A
authors.initials: AJ
authors.lastname: Cobb
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D002384:Catalysis; D003521:Cyclopropanes / Q000737:chemistry*; D015394:Molecular Structure; D011804:Quinolines / Q000737:chemistry*; D013237:Stereoisomerism; D013450:Sulfones / Q000737:chemistry*; D013997:Time Factors
chemical_list: D000596:Amino Acids; D003521:Cyclopropanes; D011804:Quinolines; D013450:Sulfones; C552577:cupreine; C030797:cyclopropane