Diversity‐Oriented Synthetic Endeavors of Newly Designed Ferrier and Ferrier‐Nicholas Systems Derived from 1‐C‐Alkynyl‐2‐deoxy‐2‐C‐Methylene Pyranosides

Abstract

Novel pyranose derivatives that display Ferrier‐ and Ferrier‐Nicholas‐like reactivity have been designed. These systems: 1‐C‐alkynyl‐2‐deoxy‐2‐C‐methylene pyranosides (Ferrier), and their corresponding dicobalthexacarbonyl alkenyl derivatives (Ferrier‐Nicholas), which can be accessed by a concise synthetic route from commercially available tri‐O‐acetyl‐d‐glucal, allow the incorporation of two nucleophiles (at positions C‐3 and C‐2′) in the pyranose ring. The study of these systems has resulted in the discovery of novel reaction patterns that allow, among others, access to open‐chain derivatives, branched pyranosides, 1,6‐anhydro derivatives and, when reacting with indole, access to a new family of tetracyclic indole‐containing carbohydrate derivatives, namely, cyclohepta[b]indole‐fused glycals. The latter are, most likely, formed by a bis Ferrier‐type rearrangement followed by an unusual intramolecular 7‐endo‐dig Friedel–Crafts alkenylation of one of the indole moieties by the C‐1 alkyne.

Recent Advances on the Synthesis of C-Glycosides from 1,2-Glycals

“…45 In 2018, Lopez et al reviewed the application of the Ferrier rearrangement towards the synthesis of C-glycosides from glycals. 46 Kinfe (2019) has comprehensively reviewed the various aspects of glycal chemistry, including the synthesis of C-glycosides and their applications towards the preparation of natural products. 47 In 2021, Hussain and Hussain broadly reviewed the recent progress on the Pd-catalyzed synthesis of C-glycosides and branched sugars.…”