Narcissus and Daffodil

324 V.N. Bulavka and O.N. Tolkachev
119
121
Ph
Ph
O
MeO
O
O
Me O
SiMe2
Me
Me
O
O
122
44
O
O
N
O
NH
N—COCF3
CF3
O
O
Ph
Ph
127 128
OH
Ph
Ph
2
HO
The dienone 119 was found easily to undergo various transformations (Figure
12.15). Thus, on trifluoroacetic acydolysis it produced narwedine-type enone 120
only. On treatment with concentrated HCl or BCl 3 , 119 selectively lost only the
trimethylsilanyl group with formation of dienone 127. In a medium of 5N HCl in
O
1
HO
N
SiMe3
MeO
NH
O
HO
O
HO
124 125 126
119
129
Figure 12.15 Synthesis of narwedine (2), galanthamine (1), lycoramine (123) and
sanguinine (126) (above) and reactions of trimethylsilanyl-substituted
narwedine-type dienone (119) (below) (Kita et al., 1998).
123
HO
O
O
HO
NMe
N
NMe
O
CF3