A range of carbohydrate derivatives containing α-ketoester functionality undergo efficient reductive loss of the acyloxy groups when treated with tri-n-butyltin hydride in refluxing benzene and in the presence of azoisobutyronitrile (AIBN) as radical initiator; under similar conditions, but with allyltri-n-butyltin instead of the hydride, efficient α-C-allylation takes place with axial substitution occurring preferentially in compounds with the ketoesters located within conformationally stable pyranoid rings; the methods represent novel ways of deoxygenating carbohydrate derivatives and of introducing branch points.
                                    当在回流苯中并在偶氮
异丁腈(AIBN)作为自由基
引发剂存在下用三正丁基氢化
锡处理时,一系列含有α-
酮酯官能团的
碳水化合物衍
生物会经历酰氧基的有效还原损失;在类似的条件下,但用烯丙基三正
丁基锡代替
氢化物,会发生有效的α-C-烯丙基化,轴向取代优先发生在
酮酯位于构象稳定的
吡喃环内的化合物中;该方法代表了
碳水化合物衍
生物脱氧和引入分支点的新方法。