Background: Pyranoid spirofused sugar derivatives represent a class of compounds with a significant impact in the literature. From the structural point of view, the rigidity inferred by the spirofused entity has made these compounds object of interest mainly as enzymatic inhibitors, in particular, carbohydrate processing enzymes. Among them glycogen phosphorylase and sodium glucose co-transporter 2 are important target enzymes for diverse pathological states. Most of the developed compounds present the spirofused entity at the C1 position of the sugar moiety; nevertheless, spirofused entities can also be found at other sugar ring positions. The main spirofused entities encountered are spiroacetals/thioacetals, spiro-hydantoin and derivatives, spiro-isoxazolines, spiro-aminals, spiro-lactams, spiro-oxathiazole and spiro-oxazinanone, but also others are present.

Objectives: The present review focuses on the most explored synthetic strategies for the preparation of this class of compounds, classified according to the position and structure of the spirofused moiety on the pyranoid scaffold. Moreover, the structures are correlated to their main biological activities or to their role as chiral auxiliaries.

Conclusion: It is clear from the review that, among the different derivatives, the spirofused structures at position C1 of the pyranoid scaffold are the most represented and possess the most relevant enzymatic inhibitor activities. Nevertheless, great efforts have been devoted to the introduction of the spirofused entity also in the other positions, mainly for the preparation of biologically active compounds but also for the synthesis of chiral auxiliaries useful in asymmetric reactions; examples of such auxiliaries are the spirofused chiral 1,3-oxazolidin-2-ones and 1,3-oxazolidine-2-thiones.

背景：吡喃类螺融糖衍生物代表了一类在文献中具有重大影响的化合物。从结构的角度来看，螺旋融合实体推断出的刚性使这些化合物主要作为酶抑制剂，特别是碳水化合物加工酶成为人们感兴趣的对象。其中糖原磷酸化酶和钠葡萄糖协同转运蛋白2是不同病理状态的重要靶酶。大多数已开发的化合物在糖部分的 C1 位呈现螺旋融合实体；然而，螺旋融合的​​实体也可以在其他糖环位置找到。遇到的主要螺合实体是螺缩醛/硫缩醛、螺乙内酰脲及其衍生物、螺异恶唑啉、螺胺醛、螺内酰胺、螺恶噻唑和螺恶嗪酮，

目的：本综述侧重于探索最多的用于制备此类化合物的合成策略，根据吡喃类支架上螺旋融合部分的位置和结构进行分类。此外，这些结构与它们的主要生物活性或它们作为手性助剂的作用相关。

结论：从综述中可以清楚地看出，在不同的衍生物中，吡喃支架 C1 位的螺旋融合结构最具代表性，并且具有最相关的酶抑制剂活性。尽管如此，人们仍致力于在其他位置引入螺旋融合实体，主要用于制备生物活性化合物，但也用于合成可用于不对称反应的手性助剂；这种助剂的例子是螺合手性1,3-恶唑烷-2-酮和1,3-恶唑烷-2-硫酮。