Our project involves the stereoselective synthesis of multi-substituted tetrahydrofuran derivatives, aimed at the development of methods for the construction of biologically important macrolides. The prepared derivatives are not suitable for the elemental analysis, but mass spectrometry (primarily FAB-MS) appears to be an ideal tool for confirming the structures of these compounds. Since the high-resolution mass spectrometry facility is unavailable in our department, the analyses were conducted by the Mass Spectrometry Facility at MSU, and were found to be accurate, efficient, and economical. We expect to request more mass analyses in the future.