In the structures of the HDV ribozyme a cytosine nucleobase resides at the active site poised to participate directly in catalysis. Defining the functional role of the nucleobase requires nucleoside analogues that perturb the functional groups in a strategic manner. Herein, we have developed efficient methods for the synthesis of five C-nucleoside phosphoramidite derivatives that, when used in combination, provide strategies for probing the potential ...
