A new approach to the stereoselective total synthesis of isotopically labeled D-ribo-phytosphingosine

We describe a novel stereoselective total synthesis of D-ribo-[1,1-H-2-1,2- C-13]phytosphingosine (12). Chirality at the incipient C-4 position was der ived from asymmetric dihydroxylation of 1-hexadecene. The remaining chiral centers were formed by Sharpless epoxidation of an allylic alcohol, followe d by benzoylcarbamate cyclization to furnish a 2-amino-1,3,4-triol derivati ve with the desired stereochemistry. The H-2 and C-13 labels were introduce d by Horner-Emmons condensation of C-13-labeled triethyl phosphonoacetate, followed by reduction of the resulting carboxylic ester with AlCl3/LiAlD4. Mass spectral results indicated the suitability of 12 as an internal standa rd for analyses by the isotope dilution method. (C) 1999 Elsevier Science L td. All rights reserved.