Synthesis of Saxitoxin

Structure of Saxitoxin

C10H17N7O4

Principal investigator	Yoshito Kishi
Publication year	1977
Synthesis type	Total
Number of steps	19 (linear)
References	J. Am. Chem. Soc. 1977, 99, 2818. Heterocycles 1980, 14, 1477.

Part 1 of 1

intermediate structure

TsOH, HO(CH2)3OH

PhMe

Reflux

intermediate structure

NH2NH2

H2O, MeOH

Reflux, 74% (2 steps)

intermediate structure

P2S5

PhH

intermediate structure

+

intermediate structure

NaHCO3

CH2Cl2

Reflux

See the Eschenmoser Sulfide Contraction

intermediate structure

KOH

MeOH

50 °C, 50% (3 steps)

intermediate structure

+

intermediate structure

Si(NCS)4

PhH

RT, 75%

See the Biginelli Reaction

intermediate structure

NH2NH2

H2O, MeOH

RT

intermediate structure

NOCl

MeOH

-50 °C

intermediate structure

PhH

90 °C

See the Curtius Rearrangement

intermediate structure

NH3

PhH

RT, 75% (4 steps)

intermediate structure

HS(CH2)3SH, BF3.OEt2

MeCN

RT, 63%

intermediate structure

(CF3CO)2O

AcOH

50 °C, 18 h, 50%

intermediate structure

NaHCO3, Et3O+ BF4-

CH2Cl2

RT

intermediate structure

EtCO2NH4

135 °C, 33% (2 steps)

intermediate structure

BCl3

CH2Cl2

0 °C

intermediate structure

Ac2O

Pyr

RT, 75% (2 steps)

intermediate structure

NBS

H2O, MeCN

15 °C

intermediate structure

MeOH

100 °C, 30% (2 steps)

intermediate structure

ClSO2NCO

HCO2H

5 °C, 50%

intermediate structure

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