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123.202 Lecture 7 - alkenes11. example
O
O
H
O
O OMe
OH
O O
OH
resiniferatoxin
©VT Jenny@Horticulture in the desert
12. example
O
O
H
O
O OMe
OH
O O
OH
resiniferatoxin
1000x
13. example
OAc OAc
OBn H2 OBn
10% Pd/C
H H
O O
O 99% O
OTBS OTBS
H
H
H
H H H
O
O
H
O
O OMe
OH
O O
resiniferatoxin
OH J. Am. Chem. Soc., 1997, 119, 12976
15. partial Z-alkene
reduction
cis
H2
Lindlar
catalyst H H
syn
addition
18. partial E-alkene
reduction
trans
Na
NH3(l) H
H
anti
addition
20. Na NH3 Na e [NH3]n
©P.P.Edwards@Oxford University
21. mechanism
e
H NH2
H H
e
H NH2
H radical
permits
H isomerisation
22. S
HO N
O
O OH O
epothilone C
example
23. S
TBSO N
O
O OTBS O
i. H2, Lindlar cat.
ii. HF
(79%)
H
H S
HO N
O
O OH O
25. step 1
H X H X
nucleophile step 2
electrophile
X
mechanism H
26. H step 1 H
H O H O
H H
nucleophile
step 2
electrophile
H H
O
mechanism H
27. H step 1 H
H O H O
H H
step 2
H O H H
O H H O
H H
28. remember
electrons
©Aidan O'Sullivan@flickr
attack δ+ or +