title: SYNTHESIS OFDE NOVOCHIRAL γ-AMINO-YNAMIDES USING LITHIATED YNAMIDES. OBSERVATION OF A UNIQUE 5-ENDO-DIGCYCLIZATION WITH AN INVERSION OFS-CENTER.
abstract: We describe herein details of our efforts in developing a highly stereoselective synthesis of denovochiral γ-amino-ynamides through additions of lithiated ynamides to Ellman-Davis chiralN-tert-butanesulfinyl imines. While additions of ynamides could be highly stereoselective even without Lewis acids, the use of BF3-OEt2completely reversed the stereoselectivity. On the other hand, additions of oxazolidinone-substituted, oxazinanone-substituted and tetrahydropyrimidinone-substituted ynamides behaved quite differently and functioned better with BF3-OEt2. The chirality of the oxazolidinone ring exerts no impact on the selectivity. This work also features a unique 5-endo-digcyclization of oxazolidinone-substituted γ-amino-ynamides that could be promoted with acid, leading to isothiazoles and 2,3-dihydro-isothiazoleS-oxides.
authors.affiliation: Division of Pharmaceutical Sciences, School of Pharmacy, and Department of Chemistry, University of Wisconsin, Madison, WI 53705, USA.
authors.forename: Xiao-Na
authors.initials: XN
authors.lastname: Wang
authors.affiliation: Division of Pharmaceutical Sciences, School of Pharmacy, and Department of Chemistry, University of Wisconsin, Madison, WI 53705, USA.
authors.forename: Richard P
authors.initials: RP
authors.lastname: Hsung
authors.affiliation: Division of Pharmaceutical Sciences, School of Pharmacy, and Department of Chemistry, University of Wisconsin, Madison, WI 53705, USA.
authors.forename: Sierra K
authors.initials: SK
authors.lastname: Fox
authors.affiliation: Division of Pharmaceutical Sciences, School of Pharmacy, and Department of Chemistry, University of Wisconsin, Madison, WI 53705, USA.
authors.forename: Ming-Can
authors.initials: MC
authors.lastname: Lv
authors.affiliation: Division of Pharmaceutical Sciences, School of Pharmacy, and Department of Chemistry, University of Wisconsin, Madison, WI 53705, USA.
authors.forename: Rui
authors.initials: R
authors.lastname: Qi