Fig. 3: Isopiperitenol as a valuable, chiral material in the syntheses of menthol, piperitol and cannabinoids.
From: Catalytic asymmetric synthesis of cannabinoids and menthol from neral
Hydrogenation reactions to 7 and 9 were performed on 1.0 mmol scale. Reactions to the cannabinoids were performed using an excess of isopiperitenol (1.1–1.5 equiv.). Isolated yields after chromatographic purification. d.r. and e.r. were determined by high-performance liquid chromatography or GC analysis. For the substrate scope of the asymmetric catalytic cyclization of α,β-unsaturated aldehydes, reactions were performed on a 0.25 mmol scale with iIDP 5. Only the main trans-diastereoisomer is depicted. d.r. and e.r. were determined by GC analysis. TMSOTf, trimethylsilyl triflate. *Reaction was performed on a 0.025 mmol scale and yield was determined by 1H NMR spectroscopy using mesitylene as internal standard. †Reaction stirred for 24 h. TMSOTf.
