862081-05-8Relevant articles and documents
Stereoselective synthesis of β-anomeric 4′-thiaspirocyclic ribonucleosides carrying the full complement of RNA-level hydroxyl substitution
Paquette, Leo A.,Dong, Shuzhi
, p. 5655 - 5664 (2005)
Stereoselective syntheses of a group of 4′-thiaspirocyclic ribonucleosides featuring both pyrimidine and purine classes and both possible configurations at C-5′ are described. Use is made of the Pummerer reaction of substrates carrying an α-oriented 2,4-dimethoxybenzoyloxy substituent at C-2 in order to gain reliable stereocontrol via neighboring group participation. Irrespective of the S or R configuration of the pivotal sulfoxide intermediates, the nucleobase is captured from the β-face. The competing process is formation of unsaturated sulfoxides, presumably via competing E2-type elimination. Although differences in reactivity between the two stereoisomeric series were noted, the common route has successfully given rise for the first time to desirable β-anomeric sulfur-containing spiroribonucleosides with minimum formation of the a-anomers.
