title: Stereoselective Synthesis of trans-Olefins by the Copper-Mediated S(N)2' Reaction of Vinyl Oxazines with Grignard Reagents. Asymmetric Synthesis of D-threo-Sphingosines.
abstract: The S(N)2' reaction of 6-vinyl-5,6-dihydro-4H-[1,3]oxazines with Grignard reagents in the presence of CuCN was studied, and high trans selectivity for the formation of double bond was observed with a variety of RMgX. The S(N)2' reaction, coupled with regioselective asymmetric aminohydroxylation reaction, provided a highly efficient route for the asymmetric synthesis of D-threo-N-acetylsphingosine.
authors.affiliation: Department of Chemistry, The University of Texas at San Antonio, San Antonio, Texas 78249, USA.
authors.forename: Om V
authors.initials: OV
authors.lastname: Singh
authors.forename: Hyunsoo
authors.initials: H
authors.lastname: Han