677346-93-9Relevant academic research and scientific papers
Ring Opening of Nucleoside 1′,2′-Epoxides with Organoaluminum Reagents: Stereoselective Entry to Ribonucleosides Branched at the Anomeric Position
Haraguchi, Kazuhiro,Kubota, Yutaka,Tanaka, Hiromichi
, p. 1831 - 1836 (2004)
Epoxidation of 3′,5′-O-(di-tert-butylsilylene)-1′ ,2′-unsaturated uridine (11) with dimethyldioxirane proceeded from the α-face to give the 1′,2′-α-epoxide 12. Upon reacting with organoaluminum reagents, the 1′,2′-α-epoxide 12 underwent preferential syn-opening of the epoxide ring to yield the β-anomers of 1′-methyl- (13β), 1′-ethyl- (14β), 1′-isobutyl- (15β), 1′-ethynyl- (16β), 1′-vinyl- (17β), and 1′-phenyl- (18β) uridine derivatives, although the corresponding α-anomers were also formed except for the reaction with triphenylaluminum. It was found, however, that protection of the N 3-position of 11 either with a benzyloxymethyl or benzoyl group led to the exclusive formation of the desired β-anomers. A possible explanation for the observed stereochemical outcome is presented. A similar strategy was found to be applicable to the synthesis of 1′-branched adenosine analogues, which include protected angustmycin C (37).
