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Direct nucleophilic displacement of the alpha-hydroxy of the propargylic alcohol is one of the sought-after methods in the current scenario. An updated summary of the recent developments in this field is presented here.

Glycosylations of armed and disarmed trichloroacetimidate‐based glycosyl donors were carried out by using the AuCl3–phenylacetylene relay catalyst system. The effectiveness of this catalytic system was also compared with that of using AuCl3 alone as a catalyst. Glycosylations with these catalysts proceeded efficiently at room temperature within 5–45 min. Excellent diastereoselectivity was obtained for the glycosylation of 2‐O‐acetyl‐protected disarmed glycosyl donors, whereas armed glycosyl trichloroacetimidates gave rise to a mixture of anomeric glycosides. Acid‐sensitive nucleophiles such as Fmoc‐serine tert‐butyl ester or Fmoc‐threonine tert‐butyl ester successfully underwent the glycosylations, albeit in moderate yields, under mild conditions at room temperature.

We have developed a new catalyst system comprising AuCl3 and phenylacetylene that promotes the Ferrier rearrangement of glycals and 2‐acetoxymethylglycals with different nucleophiles, and also the O‐glycosylation of 1‐O‐acetyl sugars to obtain a variety of useful glycosides at room temperature through relay catalysis. Good anomeric selectivity was observed for the Ferrier rearrangements, whereas the O‐glycosylation of 1‐O‐acetyl sugars gave mixtures of diastereomers with moderate to excellent selectivity.

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Synthesis of isofagomine has been achieved by implementation of aza-Claisen rearrangement of 2-C-hydroxymethyl glycals as a key step. The above rearrangement has also been utilized in the synthesis of biologically important polyhydroxylated piperidine frameworks such as isogalactofagomine, ent-isogalactofagomine and their analogues and some other azasugars as glycosidase inhibitors.

1-O-Acetylfuranoses and pyranose 1,2-orthoesters were activated with an Au III halide/phenylacetylene relay catalyst system, and they acted as excellent glycosyl donors. Thus, 1-O-acetyl-D-ribofuranose, 1-O-acetyl-D-lyxofuranose, and 1,2-