Anti-virally active carbanucleosides such as entecavir are prepared by a process which utilizes throughout the synthesis an aromatic protectant group for the hydroxyl and the alkyl hydroxy groups of the starting material removed as the final step of a multi-step synthesis. Such protectant groups yield intermediates which are solid and therefore easily purified at various stages of the process for an economical and relatively fast process for synthesizing the final product.

Provided is a process for preparing a compound of Formula (I) comprising de-protecting a compound of Formula (III) in a solvent in the presence of a Lewis acid with the properties of reduced steps and less solvent.