Practical Synthesis of Enantiopure Spiro[4.4]nonane <i>C</i>-(2‘-Deoxy)ribonucleosides
作者:Ryan Hartung、Leo A. Paquette
DOI:10.1021/jo0480601
日期:2005.3.1
The levorotatory diol 7 has been sequentially monosilylated, dehydrated, and oxidized at the allylic methylene group to provide (+)-12. The enantiomeric dextrorotatory diol 7 has been directed down a different sequence of steps involving monosilylation, dehydration, hydroboration, Swern oxidation, and regioselective introduction of a conjugated double bond to generate (−)-33. The novel feature of these
Development of a Generic Stereocontrolled Pathway to Fully Hydroxylated Spirocarbocyclic Nucleosides as a Prelude to RNA Targeting
作者:Leo A. Paquette、Ryan E. Hartung
DOI:10.1055/s-2005-918472
日期:——
Osmylation of the enantiopure conjugated enones 4 and 15 proceeded predominantly or exclusively from the α-face to give the 2′,3′-diols 6 and 16. Ensuing conversion into the acetonide allowed for sequential stereocontrolled reduction with L-Selectride, and esterification with triflic anhydride was utilized to form triflates 11 and 19. The heightened electrophilicity of these intermediates made possible SN2 displacements with several nucleobases as promoted with potassium hydride in N,N-dimethylformamide at room temperature. Suitable deprotection measures led to the targeted compounds.