doi:10.1016/S0040-4039(02)02309-2
Copyright © 2002 Elsevier Science Ltd All rights reserved.
Stereoselective synthesis of d-erythro- and l-threo-sphinganines via palladium-catalyzed equilibration and Suzuki coupling
Gregory R. Cook
, a,
and Ketheeswaran Pararajasinghama
aDepartment of Chemistry, North Dakota State University, Fargo, ND, 58105-5516, USA
Received 2 October 2002;
revised 14 October 2002;
accepted 15 October 2002.
Available online 9 November 2002.
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Abstract
The Pd-catalyzed isomerization of 5-vinyloxazolines was utilized for the stereoselective synthesis of d-erythro- and l-threo-spinganine triacetate. A hydroboration/Suzuki coupling sequence was employed to elongate the hydrophobic chain.
Scheme 3. Reagents and conditions: (a) DIBAL-H, Tol, −78°C (82%); (b) vinylmagnesium bromide, THF (59%); (c) NaH, THF, PhCOCl (60%); (d) Pd(PPh3)4, CH3CN (90%).
Scheme 4. Reagents and conditions: (a) 9-BBN, THF, Pd(PPh3)4, Z-1-bromo-tridecene, NaOH, THF (62%); (b) H2, Pd/C, EtOAc (89%); (c) 2N HCl, THF, NaOH (59%); (d) Ac2O, pyr. (58%); (e) 2N HCl, THF (77%); (f) TBSCl, imidazole (70%); (g) MeSO2Cl, Et3N (99%); (h) 9-BBN, THF, Pd(PPh3)4, Z-1-bromo-tridecene, NaOH, THF (52%); (i) H2, Pd/C, EtOAc (86%); (j) 2N HCl, THF, NaOH (66%); (k) Ac2O, pyr. (71%).