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[reaction: see text] A synthetic approach toward the liposidomycins, a family of complex nucleoside-type antibiotics, is reported based on the synthesis of epoxy-amides derived from the reaction of sulfur ylides with the uridyl aldehyde derivative 6. To this end, the epoxy-amide derivative of indoline 14 was stereoselectively prepared and, after treatment with DDQ, transformed into the corresponding N-indole epoxyamide 15. The indole 15 provides ready access to a variety of structures related to the diazepanone core present in the liposidomycins by reaction with a variety of amines.

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A synthetic approach to the tunicamycins, a complex family of nucleosides with potent antibiotic and antiviral activities is reported based on diazo chemistry. The corresponding precursors for the synthesis of tunicaminyl uracil derivatives, the non-stabilized diazo derived from 13 and the aldehyde derivative of uridine, compound 4, were prepared efficiently from commercially available D-galactal and uridine, respectively. After a high yielding coupling reaction to obtain the ketone 14, a stereoselective reduction provided the corresponding tunicaminyl uracil derivative 17a and its C-7 epimer 17b. The interconversion of the diazo and aldehyde functional groups in the requisite building blocks was similarly achieved to obtain the ketone 32, which after reduction yielded the corresponding 7-deoxy-6-hydroxy tunicaminyl uracil analogs 33a and 33b.