Stereoselective synthesis of hernandulcin, peroxylippidulcine A, lippidulcines A, B and C and taste evaluation

• Marco G. Rigamonti and
• Francesco G. Gatti

Beilstein J. Org. Chem. 2015, 11, 2117–2124, doi:10.3762/bjoc.11.228

• reagent. The taste evaluations indicate that none of these sesquiterpenes are sweet, instead the lippidulcine A is a cooling agent with a mint after taste. Keywords: ADH ketone reduction; cooling agent; Corey–Bakshi–Shibata reduction; dehydrogenation; hernandulcin; Kornblum–DeLaMare rearrangement

• . Then, the O-silyl group of 15a was cleaved with TBAF affording lippidulcine A ([α]D +132° (c 1.3, CHCl3) vs lit. [8] [α]D +123.6° (c 0.1, CHCl3)), which turned out to be a very pleasant cooling agent with a very light mint after taste (Table 3). Ketone 14 was submitted to the Corey–Bakshi–Shibata

• group on the side chain of hernandulcin has changed drastically the taste of the latter, indeed the lippidulcines B and C are bitter, whereas, very surprisingly 3a turned out to be a new natural cooling agent [38] with a light mint retro taste. These results are in contrast with the behavior of the