Synthesis of Echinosporin

Structure of Echinosporin

C10H9NO5

Principal investigatorAmos B. Smith, III
Publication year1989
Synthesis typePartial
Number of steps 16 (linear)
References
J. Am. Chem. Soc. 1989, 111, 8039. J. Am. Chem. Soc. 1992, 114, 2567.
Part 1 of 1

SM obtained in 3 steps from ascorbic acid. See J. Org. Chem. 1985, 50, 3462

intermediate structure
3,4-Dihydropyran, Pyr.TsOH
CH2Cl2
RT, 12 h, 100%
intermediate structure
i-Bu2AlH
CH2Cl2
-78 °C, 1 h, 100%
intermediate structure
Pyr.TsOH
MeOH
RT, 3 h
intermediate structure
H2SO4
Acetone
0 °C to RT, 2 h, 53% (2 steps)
intermediate structure
  1. (COCl)2 , DMSO , Et3N
  2. TsNHNH2
CH2Cl2
-78 °C to RT, 35 min
See the Swern Oxidation
intermediate structure
NaOCH2CH2OH
Ethylene Glycol
120 °C, 1 h, 83% (2 steps)
See the Bamford-Stevens Reaction
intermediate structure
2-Cyclopentenone
hv
Pentane
RT, 22 h, 50%
"Also isolated were other regio and stereoisomers (29%)"
intermediate structure
  1. i-Pr2NLi
  2. PhNTf2
THF
-78 to -20 °C, 24 h, 76%
intermediate structure
Et3N, Pd(OAc)2, Ph3P, CO
DMF, MeOH
RT, 20 h, 83%
intermediate structure
  1. TMS2NK
  2. (+)-(Camphorsulfonyl)oxaziridine
HMPA, PhMe, THF
-78 °C, 2 h, 90 %
See the Davis Asymmetric Hydroxylation
intermediate structure
Bio-Rad AG50W-X2 resin
H2O, MeCN
RT, 3 d, 69%
intermediate structure
Pd2(dba)3, Diallyl carbonate
CHCl3, MeCN
80 °C, 3 h, 54%
intermediate structure
NH3
H2O, MeOH
RT, 20 h, 86%
intermediate structure
DMSO, Et3N, Pyr.SO3
CH2Cl2
0 °C, 65 min, 46%
See the Parikh-Doering Oxidation
intermediate structure
HCl
H2O
RT, 48 h, 100%
intermediate structure
n-Bu3P, DEAD
4A MS
THF
-15 °C to RT, ON, 30%
See the Mitsunobu Reaction
intermediate structure
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