Chemoenzymatic Convergent Synthesis of 2′‑O,4′‑C‑Methylene­ribonucleosides

Novozyme-435-catalyzed efficient regio­selective acetylation of one of the two dia­stereo­topic hydroxy­methyl functions in 3-O-benzyl-4-C-hydroxy­methyl-1,2-O-iso­propylidene-α-d-ribo­furanose has been achieved. The enzymatic methodology has been successfully utilized for convergent synthesis of bicyclic nucleosides (LNA monomers) T, U, A, and C. Further, it has been demonstrated that Novozyme-435 can be used for 10 cycles of the acylation reaction without losing selectivity and efficiency.