Synthesis of Cholesterol

C27H46O
Principal investigator | Robert B. Woodward |
---|---|
Publication year | 1951 |
Synthesis type | Formal |
Number of steps | 35 (linear) |
References |
Part 1 of 1
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NaOH
Dioxane , H2O
40-50 °C, 90%

LiAlH4
THF
Reflux, 65 min, 64%

H2SO4
Dioxane , H2O
RT, 24 h, 99%

Ac2O
Pyr
RT, 12 h, 96%

Zn
Ac2O
Reflux, 8 min, 63%



KOH
Dioxane , H2O
0 °C, 3 h, 88%

OsO4
Et2O
0 °C, 5-8 d, 57%
"A single, uncharacterized isomer was isolated."

CuSO4
Acetone
RT, 36 h, 83%

Pd/SrCO3,
H2
1 atm
PhH
RT, 3.5 h, 85%


PhNHMe
MeOH
RT, 24 h, 88% (2 steps)


KOH
H2O
Reflux, 46% (2 steps)
"Also isolated was the C1-epimer (33 % yield)."

NaOAc
Ac2O
Reflux, 2 h, 28%



HIO4
Dioxane , H2O
0 °C, 14 h


Na2Cr2O7
AcOH, H2O
RT, 10 h

CH2N2
Et2O, PhH
RT, 20 min, 30% (2 steps)

H2,
PtO2
1 atm
AcOH
RT

CrO3
AcOH
RT, ON, 2.4% (2 steps)

NaBH4
EtOH
RT, 4 h, 64%

KOH
H2O, MeOH
Reflux, 12 h, 100%

Ac2O
Pyr
60 °C, 3 h, 92%

SOCl2
0 °C to RT, 15.5 h, 90%

MeCd
PhH
Reflux, 90 min, 92%



Ac2O
AcOH
Reflux, 2.5 h

PtO2,
H2
AcOH
RT, 30 min, 14% (3 steps)

KOH
H2O, MeOH
Reflux, 2 h, 85%

Remaining...
(5 steps)
"See : Org. Synth. 1937, 17, 43; Ber. 1935, 68, 2091; Helv. Chim. Acta 1938, 21, 866; J. Chem. Soc. 1950, 2325."
