Synthesis of Ginkgolide B

C20H24O10

Principal investigator	Elias J. Corey
Publication year	1988
Synthesis type	Total
Number of steps	26 (2 parts)
References	J. Am. Chem. Soc. 1988, 110, 649.

Part 1 of 2

(COCl)2

PhH

RT, 85%

BF3.OEt2

CH2Cl2

-20 °C, 92%

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Part 2 of 2

Glyoxal dimethyl acetal

PhH

RT, 18 h, 70%

See the Stork Enamine Synthesis

CuCN , t-BuLi
TMSCl

Et2O, Et3N

-78 to -10 °C, 3 h, 93%

See the Michael Addition

(CH2O)3, TiCl4

MeOH

-78 °C to RT, 16 h, 65%

See the Mukaiyama Aldol Addition

i-Pr2NLi
PhNTf2

DME

-78 °C to RT, 4 h, 80%

CuI, n-PrNH2, Pd(PPh3)4

PhH

16 °C, 4 h, 76%

See the Sonogashira Coupling

Cy2BH
AcOH

THF

0 °C to RT, 18.5 h, 70%

(COCl)2, n-Bu3N

PhH, PhMe

RT to Reflux, 3 h, 71%

NaOH, Ph3COOH

Acetone, H2O

-30 °C, 2 h, 86%

See the Baeyer-Villiger Oxidation

TiCl4, HS(CH2)3SH

CH2Cl2

0 °C to RT, 50 min, 98%

H2Cr2O7.2Pyr, AcOH

3 Å MS

CH2Cl2

0 °C, 60 min, 75%

HIO4, H2O

CH2Cl2, MeOH

-30 °C to RT, 60 min, 80%

Camphorsulfonic acid

MeOH

RT, 80%

Et2NLi

-25 to 0 °C, 45 min

Camphorsulfonic acid

CH2Cl2

RT, 24 h, 75% (2 steps)

NBS

hν

CCl4

10 °C, 3 h

See the Wohl-Ziegler Reaction

AgNO3

MeCN

RT, 15 min, 50%

"Also isolated were two allylic nitrates, both of which were converted to the desired product. The overall yield for these transformations is shown."

Pyr, Pyr.TsOH

PhCl

135 °C, 16 h, 80%

Et3NBn+ i-PrO-, Ph3COOH

THF

-10 °C, 3 h, 72%

See the Michael Addition

i-Pr2NLi, EtCO2t-Bu

HMPA, THF

-78 to -30 °C, 12 h, 60%

See the Aldol Addition

Camphorsulfonic acid

CH2Cl2

RT, 15 h, 82%

TBSOTf, 2,6-Lutidine

MeCN

RT, 60 min, 89%

OsO4

Pyr

I2, CaCO3

MeOH

RT, 12 h, 40% (2 steps)

BF3.OEt2

CH2Cl2

RT, 14 h, 89%

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