Catalytic Stereoselective Synthesis of β-Ribonucleosides from Methyl Ribofuranosyl Carbonate and Trimethylsilylated Nucleoside Bases by Combined Use of Silver Salts and Diphenyltin Sulfide
Catalytic stereoselective synthesis of several ribonucleosides from 2,3,5-tri-O-benzoyl-β-D-ribofuranosyl methyl carbonate and trimethylsilylated nucleoside bases is efficiently carried out by combined use of silver salts and diphenyltin sulfide (Ph2Sn=S) under mild conditions.
Several beta-D-ribonucleosides were synthesized in high yields under mild conditions by N-glycosylations of methyl 2,3,5-tri-O-benzoyl-beta-D-ribofuranosyl carbonate (1) with trimethylsilylated nucleoside bases in acetonitrile using a catalytic amount of metal iodide such as SnI2, SbI3 or TeI4. A deprotection of N-6-benzoyl group of coupling product took place to a considerable extent when N-6-benzoyl-N-6,N-9-bis(trimethylsilyl)adenine was employed as a nucleoside base using SnI2 or SnCl2 as a catalyst while it was minimized when SbI3 or TeI4 was used. Further, the N-glycosylation of 1 with 7-trimethylsilyltheophylline in the presence of a catalytic amount of metal iodide was more effectively achieved in nitrile solvents other than acetonitrile.
Synthesis of N6,2’,3’,5’-Tetrabenzoyl-b-D-adenosine Catalyzed by Metal Iodides
methyl 2,3,5-tri-O-benzoyl-β-D-ribofuranosyl carbonate and trimethylsilylated nucleoside bases such as pertrimethylsilylated uracil and adenine under mild conditions by using a catalytic amount of tin(II) chloride, a weak Lewis acid.
β-D-Ribonucleosides are stereoselectively synthesized in high yields from methyl 2,3,5-tri-O-benzoyl-β-D-ribofuranosyl carbonate and trimethylsilylated nucleoside bases by the use of [diphenyltin sulfide/silver salt] or [Lawesson’s reagent/silver salt] combined catalyst system under mild conditions.