Radical-initiated 1,2-acyloxy migration which generates a nucleoside anomeric radical
摘要:
Face-selectivity of bromo-pivaloyloxylation to 1'2'-unsaturated uridine can be altered by changing the 3'5'-O-protecting group. The resulting 2'-bromo-1'-pivaloyloxylated adduct, upon being reacted under radical conditions, undergoes 1,2-acyloxy migration to generate a nucleoside anomeric radical which was allowed to react with Bu(3)SnH or allyltributyltin. Factors governing stereochemistry and efficacy of this migration are also discussed.