Formal Total Synthesis of (+)-C9-Deoxyomuralide from l-Leucine Using a Double Sacrificial Chirality Transfer Approach.

Formal stereocontrolled syntheses of (±)- and (+)-C9-deoxyomuralide is reported, constituting one of the shortest routes to the full carbon skeleton reported to date.

Triazole biotin: a tight-binding biotinidase-resistant conjugate.

The natural amide bond found in all biotinylated proteins has been replaced with a triazole through CuAAC reaction of an alkynyl biotin derivative. The resultant triazole-linked adducts are shown to be highly resistant to the ubiquitous hydrolytic enzyme biotinidase and to bind avidin with dissociation constants in the low pM range. Application of this strategy to the production of a series of biotinidase-resistant biotin-Gd-DOTA contrast agents is demonstrated.