Enantioselective Route to Platensimycin P. Li,J. N. Payette, H. Yamamoto, JACS 2007, 129, 9534-9535
K. C. Nicolaou, A. Li, D. J. Edmonds, Angew. Chem. Int. Ed. 2006, 45, 70867090
A
1
1) A, B+C 2 mol%,
1) Please draw 3D transition state to explain the stereochemistry
COOMe
F
Tf
F
N
B O
Ph
COOMe
Ph
Ph
B
endo product
D
2) LDA, THF, -78 °C
then PhNO
3) LiOH, dioxane/H2O
2,3
2+3) Please propose a mechanism
O
E
4
4) Name the reaction
4) H2O2/NaOH
then acid
A: Baeyer-Villiger
F
F
F
C
H
Tf
O
O
H
F
5) CuBr Me2S
5,6
MgBr
6) 4.5 mol% HNTf2
O
O
H
dr = 10:1
G
7
O
7) DIBAL-H
then Et2AlCN, BF3 OEt2
7) How can you convert the undesired stereoisomer into desired one?
CN
H
A: deprotonation with LiHMDS followed by aqueous work up
dr = 2:3 G/G'
H
8) DIBAL-H/n-BuLi
9) NaH
O
O
8,9
P OEt
OEt
O
O
H
I
10) NaIO4, 3.5 mol% RuCl3
10
O
OHC
O
H
J
11,12
11) L-proline, 5 days
12) 2N NaOH
O
O
K
13) KHMDS, MeI
14) KHMDS,
I
13-15
15) Grubbs II,
Me O
B
Me
O
Me Me
O
B
O
O
O
L
15) Draw Grubbs II
16) Me3NO
17) NaClO2
18) HATU, NEt3,
16-19
OMOM
NH2
OMOM
COOMe
OH
H
N
O
19) LiOH; then HCl
O
OH
COOH
O
platensimycin
M
17) Name the reaction
A: Pinnick oxidation