title: α- and α'-Lithiation-Electrophile Trapping of N-Thiopivaloyl and N-tert-Butoxythiocarbonyl α-Substituted Azetidines: Rationalization of the Regiodivergence Using NMR and Computation.
abstract: (1)H NMR and computational analyses provide insight into the regiodivergent (α- and α'-) lithiation-electrophile trapping of N-thiopivaloyl- and N-(tert-butoxythiocarbonyl)-α-alkylazetidines. The magnitudes of the rotation barriers in these azetidines indicate that rotamer interconversions do not occur at the temperature and on the time scale of the lithiations. The NMR and computational studies support the origin of regioselectivity as being thiocarbonyl-directed lithiation from the lowest energy amide-like rotameric forms (cis for N-thiopivaloyl and trans for N-tert-butoxythiocarbonyl).
authors.affiliation: Department of Chemistry, Chemistry Research Laboratory, University of Oxford , Mansfield Road, Oxford OX1 3TA, U.K.
authors.forename: Kelvin E
authors.initials: KE
authors.lastname: Jackson
authors.affiliation: Department of Chemistry, Chemistry Research Laboratory, University of Oxford , Mansfield Road, Oxford OX1 3TA, U.K.
authors.forename: Claire L
authors.initials: CL
authors.lastname: Mortimer
authors.affiliation: Department of Chemistry, Chemistry Research Laboratory, University of Oxford , Mansfield Road, Oxford OX1 3TA, U.K.
authors.forename: Barbara
authors.initials: B
authors.lastname: Odell
authors.affiliation: Novartis Institutes for BioMedical Research , Wimblehurst Road, Horsham, West Sussex RH12 5AB, U.K.
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: McKenna
authors.affiliation: Department of Chemistry, Chemistry Research Laboratory, University of Oxford , Mansfield Road, Oxford OX1 3TA, U.K.
authors.forename: Timothy D W
authors.initials: TD
authors.lastname: Claridge
authors.affiliation: Department of Chemistry, Chemistry Research Laboratory, University of Oxford , Mansfield Road, Oxford OX1 3TA, U.K.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Paton
authors.affiliation: Department of Chemistry, Chemistry Research Laboratory, University of Oxford , Mansfield Road, Oxford OX1 3TA, U.K.
authors.forename: David M
authors.initials: DM
authors.lastname: Hodgson
mesh_terms: D001384:Azetidines / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D011789:Quantum Theory; D013438:Sulfhydryl Compounds / Q000737:chemistry*
chemical_list: D001384:Azetidines; D013438:Sulfhydryl Compounds