S. Esaki et al., PREPARATION AND TASTE OF CERTAIN GLYCOSIDES OF FLAVANONES AND OF DIHYDROCHALCONES, Bioscience, biotechnology, and biochemistry, 58(8), 1994, pp. 1479-1485
The [2-O-(alpha-L-Rhamnopyranosyl)-beta-L-quinovoside] of naringenin a
nd of hesperetin, and their dihydrochalcone (DHC) derivatives were syn
thesized by the method of Koenigs-Knorr (Ag,CO, and quinoline). The re
action of TMS ethers of naringenin and of hesperetin with each of the
alpha-acetofluoro derivatives of D-glucose, L-rhamnose, 2-O-(alpha-L-r
hamnopyranosyl)-L-rhamnose, and 2-O-(alpha-L-rhamnopyranosyl)-D-glucos
e (neohesperidose), using boron trifluoride etherate as an activator,
yielded coupling products which, after deprotection, gave naringenin 4
-O-beta-D-glucoside, naringenin 4'-O-alpha-L-rhamnoside naringenin 2-O
-(alpha-L-rhamnopyranosyl)-alpha-L-rhamnoside], hesperetin 2-O-(alpha-
L-rhamnopyranosyl)-alpha-L-rhamnoside], and naringenin 4'-O-beta-neohe
speridoside, respectively. Catalytic hydrogenation of these flavanones
gave the corresponding DHC derivatives. Hesperetin DHC -[2-O-(alpha-L
-rhamnopyranosyl-beta-L-quinovoside] was 300 times sweeter than sucros
e, while the other compounds were bitter or tasteless.