New RNA Purine Building Blocks, 4′‐Selenopurine Nucleosides: First Synthesis and Unusual Mixture of Sugar Puckerings

Abstract

Writer's blocks: The first synthesis of RNA purine building blocks, 4'-selenoadenosine and 4'-selenoguanosine was achieved from D-ribose by regioisomeric rearrangement, which was confirmed by X-ray crystallography. 4'-Selenoadenosine exists in an unusual mixture of north and south conformers in the solid state.