ABSTRACT
The highly diastereoselective anti-aminohydroxylation of (E)-gamma-tri-iso-propylsilyloxy-alpha,beta-unsaturated esters, via conjugate addition of lithium (S)-N-benzyl-N-(alpha-methylbenzyl)amide and subsequent in situ enolate oxidation with (+)-(camphorsulfonyl)oxaziridine, has been used as the key step in the asymmetric synthesis of N,O,O,O-tetra-acetyl d-lyxo-phytosphingosine (20% yield over 7 steps), the anhydrophytosphingosine jaspine B (10% yield over 9 steps), 2-epi-jaspine B (14% yield over 9 steps), and the Prosopis alkaloid deoxoprosophylline (26% yield over 7 steps).
Subject(s)
Amides/chemistry , Benzylamines/chemistry , Lithium/chemistry , Organometallic Compounds/chemistry , Piperidines/chemical synthesis , Sphingosine/analogs & derivatives , Molecular Conformation , Oxidation-Reduction , Piperidines/chemistry , Sphingosine/chemical synthesis , Sphingosine/chemistry , StereoisomerismABSTRACT
This article describes the design of olefin-generated/reagent-modulated consecutive hetero-domino reactions of 1,2-unsaturated bicyclic diols, which are potentially of great use, initiated by PhI(OAc)(2), continued by [Pb(OAc)(4)], and completed by use of a mild base (K(2)CO(3)). Inversion of a quaternary center has been achieved through a three-reaction sequence: a domino transformation followed by an m-CPBA-mediated Baeyer-Villiger oxidation and subsequent reductive lactone ring opening.