Synthesis of Sarain A

C32H50N2O3
Principal investigator | Larry E. Overman |
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Publication year | 2007 |
Synthesis type | Total |
Number of steps | 51 (3 parts) |
References |
Part 1 of 3
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NaBH4,
BH3.Me2S
THF
0 °C to RT, 26 h, 54%

Imidazole,
TBDPSCl
THF
0 °C to RT, 52 h, 82%

H2,
Pd/C
1 atm
EtOAc
RT, 24 h


CH2Cl2
RT, 24 h, 73% (2 steps)

Part 2 of 3


- n-BuLi
- ClCO2Me
THF
-78 °C to RT, 92%

H2,
Lindlar Catalyst
1 atm
PhMe
RT, 3 h, 99%

Part 3 of 3
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DMSO
180 °C, 60 min, 69%

AlMe3
PhMe
RT, 90 min, 91%

- TMS2NLi
- AllylBr
THF, DMPU
-78 to -55 °C, 25 h, 92%

HCl
H2O, THF
RT, 48 h, 98%

Boc2O,
DMAP
MeCN
RT, 15 h, 96%

i-Bu2AlH
CH2Cl2
-78 °C, 25 min

NaBH3CN
AcOH
RT, 12 h, 93% (2 steps)

DMSO
130 °C, 4.5 h

n-Bu4N+ F-,
Ac2O
Et3N, THF
70 °C, 16 h
"R = H or Ac (mixture)"

K2CO3
MeOH
RT, 12 h, 68% (3 steps)
"R = H or Ac (mixture)"

i-Bu2AlH
CH2Cl2
-78 °C, 5 h, 87%

NaOMe
THF
0 °C to RT, 4 h


Et3N,
Triphosgene
CH2Cl2
0 °C, 45 min, 92% (2 steps)

- O3 , NaHCO3
- Me2S
CH2Cl2, MeOH
-78 °C to RT, 12 h, 92%





HF
H2O, MeCN
91% (2 steps)

TIPSOTf,
Et3N
CH2Cl2
-78 °C to RT, 12 h, 97%


TBSCl,
Imidazole
MeCN
RT, 2 h

NaBH4
MeOH
0 °C, 2 h

TIPSOTf,
Et3N
CH2Cl2
RT, 48 h, 75% (3 steps)

Naphtalene,
Na
DME, THF
-78 °C, 84%


NaBH3CN,
AcOH
4 Å MS
MeCN
RT, 25 min, 94%


Pd/C,
H2
1 atm
EtOAc
RT, 6 h, 82% (2 steps)

HCl
H2O, THF
RT, 6 h, 95%

- TMS2NNa
- (4-MeOPh)CH2Cl
DMF
RT, 30 min, 89%

TASF
DMA
100 °C, 60 min

KOH
EtOH
90 °C, 12 h, 65% (2 steps)


PhH
80 °C, 3 h, 86%

IBX
DMSO
RT, 105 min, 71%



n-Bu4N+ F-
THF
RT, 105 min, 85%

TESCl,
Imidazole
DMF
0 °C, 15 min, 70%

K2CO3
MeOH
0 °C to RT, 13 h, 92%





i-Bu2AlH
PhMe
-78 to 0 °C, 25 min, 64% (2 steps)


Pyr.HF
CH2Cl2
0 °C, 90 min, 49% (2 steps)
