Synthesis of Echinosporin

Structure of Echinosporin

C10H9NO5

Principal investigatorAmos B. Smith, III
Publication year1989
Synthesis typePartial
Number of steps 16 (linear)
References
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)
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 %
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%
intermediate structure
HCl
H2O
RT, 48 h, 100%
intermediate structure
n-Bu3P, DEAD
4A MS
THF
-15 °C to RT, ON, 30%
intermediate structure