Efficient Synthesis of Enantiomerically Pure 2-Acylaziridines:  Facile Syntheses of <i>N</i>-Boc-safingol, <i>N</i>-Boc-<scp>d</scp><i>-erythro</i>-sphinganine, and <i>N</i>-Boc-spisulosine from a Common Intermediate

Abstract

Various enantiomerically pure 2-acylaziridines were prepared efficiently from the corresponding aziridine-2-carboxylate via Weinreb's amide and the subsequent treatment of organometallic compounds. The carbonyl group of those 2-acylaziridines was stereoselectively reduced by NaBH4in the presence of ZnCl2 to give erythro-1,2-amino alcohols with high diastereoselectivities and chemical yields. Using this methodology, we prepared (1R,2S)-N-Boc-norephedrine 5, N-Boc-safingol 8, N-Boc-D-erythro-sphinganine 9, and N-Boc-spisulosine 10 in high yields.