Syntheses and olfactory characteristics of flavouring and perfuming lactone thiono-analogues

Thionation of several γ‐, δ‐ and ε‐lactones widely used in flavours and fragrances was carried out using three different synthetic procedures. γ‐Thionolactones were synthesized via a microwave‐assisted procedure, whereas δ‐ and ε‐thionolactones were prepared using Lawesson's reagent or the P4S10–HMDO combination under standard conditions. The synthesized compounds were submitted to an olfactory evaluation: γ‐thionolactones offered a large variety of odours related to saffron, mushrooms and fruits, while δ‐thionolactones presented a strong character of sulphur with a poor variety of olfactory notes. cis‐Jasmone thionolactone, 6‐amylthionopyrone, and menthone thionolactone presented very interesting notes of blackcurrant, Tagetes minuta and celery, respectively. Copyright © 2005 John Wiley & Sons, Ltd.