227
To determine the structure of the natural bisabolane compound 682, a component
of L. lankongensis, all four possible stereoisomers were synthesized (Scheme 30)
[343]. Starting from (−)-carvone ((−)-1108), compounds 1229a–1229c,
1230a–1230c, 1231a–1231c, and 1232a–1232c (a, acetate; b, angelate; c, tiglate)
were synthesized by an analogous route via 1227 and 1228. Both the
1
H and
13
C
NMR data were assigned and compared to discern that diangelate 1230b was
Scheme 29 Synthesis of diastereoisomers of chiral bisabolanes by Kuroda’s group
Scheme 30 Synthesis of highly oxygenated chiral bisabolanes by Kuroda’s group
Chemical Constituents of Ligularia Species (Asteraceae) and Their Diversity…
To determine the structure of the natural bisabolane compound 682, a component
of L. lankongensis, all four possible stereoisomers were synthesized (Scheme 30)
[343]. Starting from (−)-carvone ((−)-1108), compounds 1229a–1229c,
1230a–1230c, 1231a–1231c, and 1232a–1232c (a, acetate; b, angelate; c, tiglate)
were synthesized by an analogous route via 1227 and 1228. Both the
1
H and
13
C
NMR data were assigned and compared to discern that diangelate 1230b was
Scheme 29 Synthesis of diastereoisomers of chiral bisabolanes by Kuroda’s group
Scheme 30 Synthesis of highly oxygenated chiral bisabolanes by Kuroda’s group
Chemical Constituents of Ligularia Species (Asteraceae) and Their Diversity…