title: Nucleic Acid Related Compounds. 105. Synthesis of 2',3'-Didehydro-2',3'-dideoxynucleosides from Ribonucleoside Cyclic 2',3'-(Sulfates or Phosphates) or 2',3'-Dimesylates via Reductive Elimination with Sodium Naphthalenide(1).
abstract: Treatment of purine ribonucleosides with thionyl fluoride resulted in formation of cyclic 2',3'-sulfite esters. Acetylation of the 5'-hydroxy group and Sharpless oxidation (NaIO(4)/RuCl(3)) gave the cyclic 2',3'-sulfate ester derivatives. Treatment of 5'-O-silyl-protected ribonucleosides with thionyl chloride followed by oxidation gave an alternative route to the cyclic 2',3'-sulfates. Reductive elimination with sodium naphthalenide (THF/-50 degrees C) gave the 2',3'-unsaturated nucleosides. Parallel treatment of adenosine cyclic 2',3'-phosphate gave the 2',3'-olefin. The adenine, hypoxanthine, and 2-amino-6-methoxypurine 2',3'-didehydro-2',3'-dideoxynucleosides were prepared efficiently (40-60% overall yields of crystalline, analytically pure products; 3-5 steps, some combined into one-flask procedures) by treatment of 5'-O-protected 2',3'-di-O-mesylribonucleosides with sodium naphthalenide. Reactions were performed at or below ambient temperature with readily available reagents and standard laboratory conditions.
authors.affiliation: Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602-5700.
authors.forename: Morris J.
authors.initials: MJ
authors.lastname: Robins
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Lewandowska
authors.forename: Stanislaw F.
authors.initials: SF
authors.lastname: Wnuk