Synthesis of the allelochemical alliarinoside present in garlic mustard (Alliaria petiolata), an invasive plant species in North America

• Efficient, practical, and stereospecific synthesis of alliarinoside and its isomer.
• Development starting from β-d-glucopyranose pentaacetate via a simple reaction sequence.
• The method offers a straightforward route to the synthesis and isolation of alliarinoside and its isomer.

The allelochemical alliarinoside present in garlic mustard (Alliaria petiolata), an invasive plant species in North America, was chemically synthesized using an efficient and practical synthetic strategy based on a simple reaction sequence. Commercially available 1,2,3,4,6-penta-O-acetyl-β-d-glucopyranose was converted into prop-2-enyl 2′,3′,4′,6′-tetra-O-acetyl-β-d-glucopyranoside and subjected to epoxidation. In a one-pot reaction, ring-opening of the epoxide using TMSCN under solvent free conditions followed by treatment of the formed trimethylsilyloxy nitrile with pyridine and phosphoryl chloride, afforded the acetylated β-unsaturated nitriles (Z)-4-(2′,3′,4′,6′-tetra-O-β-d-glucopyranosyloxy)but-2-enenitrile and its isomer (E)-4-(2′,3′,4′,6′-tetra-O-β-d-glucopyranosyloxy)but-2-enenitrile. Deacetylation of Z- and/or E-isomers afforded the target molecules alliarinoside and its isomer.

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