EXPEDITIOUS SYNTHESES OF SUGAR-MODIFIED NUCLEOSIDES AND COLLECTIONS THEREOF EXPLOITING FURAN-BASED, PYRROLE-BASED, AND THIOPHENE-BASED SILOXY DIENES

A series of individual sugar-modified pyrimidine nucleosides including enantiomerically enriched 2',3'-dideoxynucleosides 14a-c (alpha and b eta anomers of L- and D-series), 2',3'-dideoxy-4'-thionucleosides 21a- c (alpha and beta anomers of L- and D-series), and 2',3'-dideoxy-4'-az anucleosides 28a-c (beta anomers of L- and D-series) were synthesized, with uniform chemistry and high stereochemical efficiency, exploiting a triad of versatile heterocyclic siloxy dienes, namely, 2-(tert-buty ldimethylsiloxy)furan (TBSOF), 2-(tert-butyldimethylsiloxy)thiophene ( TBSOT), and utoxycarbonyl)-2-(tert-butyldimethylsiloxy)pyrrole (TBSOP) . The synthetic procedure advantageously used both enantiomers of glyc eraldehyde acetonide (D-1 and L-1) as sources of chirality and as synt hetic equivalents of the formyl cation. The outlined chemistry also al lowed for the rapid assemblage of a 30-member collection of racemic nu cleosides (D,L-L) as well as one 15-member ensemble of chiral analogue s (L-L), along with some related sublibraries.