Ring Opening of Nucleoside 1‘,2‘-Epoxides with Organoaluminum Reagents: Stereoselective Entry to Ribonucleosides Branched at the Anomeric Position
作者:Kazuhiro Haraguchi、Yutaka Kubota、Hiromichi Tanaka
DOI:10.1021/jo030262u
日期:2004.3.1
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
从α面开始用二甲基二环氧乙烷将3',5'- O-(二叔丁基亚甲硅烷基)-1',2'-不饱和尿苷(11)环氧化,得到1',2'-α-环氧化合物12。在与有机铝试剂反应,1' ,2'-α环氧化物12后行优先顺式开口环氧化物环中以得到1'-甲基- (的β端基异构体13 β),1'-乙基- (14 β),1'-异丁基- (15 β),1'-乙炔基(16 β),1,1'-乙烯基- (17 β)和1'-苯基- (18 β)尿苷衍生物,尽管除了与三苯基铝反应以外,还形成了相应的α-端基异构体。然而,发现用苄氧甲基或苯甲酰基保护11的N 3-位可导致所需β-端基异构体的排他性形成。提出了可能的解释所观察到的立体化学结果。发现类似的策略适用于1'-支链腺苷类似物的合成,其中包括受保护的阿古霉素C(37)。