Synthesis of Yohimbine

Structure of Yohimbine

C21H26N2O3

Principal investigatorEugene E. van Tamelen
Publication year1958
Synthesis typeFormal
Number of steps 20 (linear)
References
J. Am. Chem. Soc. 1958, 80, 5006. J. Am. Chem. Soc. 1969, 91, 7315.
Part 1 of 1
intermediate structure + intermediate structure
PhH
RT, 2-3 weeks, 93%
See the Diels-Alder Reaction
intermediate structure
Zn
AcOH
30-50 °C, 40 min, 93%
intermediate structure
KOt-Bu, ClCH2CO2Et
PhH, t-BuOH
RT, ON, 81%
See the Darzens Condensation
intermediate structure
NaOH
H2O
RT to 100 °C, 45 min, 87%
intermediate structure
Cu
Diethylene glycol
155-160 °C, 2 h, 76%
intermediate structure
AgNO3, KOH
EtOH, H2O
RT, 12 h, 38%
See the Tollens Oxidation
intermediate structure
(COCl)2, Pyr
Et2O
RT, 8 h
intermediate structure + intermediate structure
Pyr
CHCl3
5 °C, 10 h, 75% (2 steps)
intermediate structure
Pyr, OsO4
Et2O, THF
-78 °C, 2.5 h, 56%
"Single, unidentified cis-isomer. Also isolated was the other cis-diastereoisomer (11 % yield)."
intermediate structure
PtO2, H2
EtOH
RT, 60 min, 85%
intermediate structure
H3PO4, NaIO4
Acetone, H2O
60-70 °C, 20 min, 60%
See the Pictet-Spengler Reaction
intermediate structure
TsOH
MeOH
RT, 3 d, 77%
intermediate structure
LiAlH4
THF
Reflux, 4 h, 76%
intermediate structure
HCl
H2O
100 °C, 3 h, 82%
intermediate structure
Ac2O
Pyr
RT, ON
intermediate structure
285-295 °C, 5 min, 71% (2 steps)
intermediate structure
OsO4, Pyr
THF
-78 °C, 7 h, 37%
intermediate structure
NaIO4
H2O, MeOH
0 °C, 2 h, 81%
intermediate structure
CrO3, H2SO4
Acetone, H2O, MeOH
0 °C, 30 min, 16%
See the Jones Oxidation
intermediate structure
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Remaining...
65% (2 steps)
"See : Acta Chim. Scand. 1956, 10, 1414."
intermediate structure