Efficient Pd(0)-catalyzed synthesis of 1,2,3-triazolo-3′-deoxycarbanucleosides and their analogues

The racemic synthesis of hitherto unknown 5-substituted-[1,2,3]-triazolo-3′-deoxycarbanucleosides and [1,2,3]-triazolo-[4,5-c]pyridin-4-one analogues is described. The key iodinated intermediate was prepared in 10 steps using a malonic synthesis. Various alkynes were introduced at the C-5 position of under optimized Pd(0)-catalyzed Sonogashira cross-coupling alkynylation to yield after deprotection . The synthesis of their 8-aza-3-deazapurine analogues () was also accomplished through the heteroannulation of internal alkynes under aqueous dimethylamine.