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Controlling the stereoselectivity of 1,2-<i>cis</i> glycosylation is one of the most challenging tasks in the chemical synthesis of glycans. There are various 1,2-<i>cis</i> glycosides in nature, such as α-glucoside and β-mannoside in glycoproteins, glycolipids, proteoglycans, microbial polysaccharides, and bioactive natural products. In the structure of polysaccharides such as α-glucan, 1,2-<i>cis</i> α-glucosides were found to be the major linkage between the glucopyranosides. Various regioisomeric linkages, 1→3, 1→4, and 1→6 for the backbone structure, and 1→2/3/4/6 for branching in the polysaccharide as well as in the oligosaccharides were identified. To achieve highly stereoselective 1,2-<i>cis</i> glycosylation, including α-glucosylation, a number of strategies using inter- and intra-molecular methodologies have been explored. Recently, Zn salt-mediated <i>cis</i> glycosylation has been developed and applied to the synthesis of various 1,2-<i>cis</i> linkages, such as α-glucoside and β-mannoside, via the 1,2-<i>cis</i> glycosylation pathway and β-galactoside 1,4/6-<i>cis</i> induction. Furthermore, the synthesis of various structures of α-glucans has been achieved using the recent progressive stereoselective 1,2-<i>cis</i> glycosylation reactions. In this review, recent advances in stereoselective 1,2-<i>cis</i> glycosylation, particularly focused on α-glucosylation, and their applications in the construction of linear and branched α-glucans are summarized.