Synthesis of Hirsutene

C15H24

Principal investigator	Tarun K. Sarkar
Publication year	1990
Synthesis type	Formal
Number of steps	16 (linear)
References	Tetrahedron Lett. 1990, 31, 3465. Tetrahedron 1992, 48, 6897.

Part 1 of 1

3,4-Dihydropyran, TsOH

Et2O

Reflux, 5 h, 45%

(COCl)2, DMSO, Et3N

CH2Cl2

-60 °C to RT, 50 min, 80%

See the Swern Oxidation

TMS2NNa

THF

-78 °C to RT, ON, 61%

See the Wittig Reaction

TsOH

MeOH

Reflux, 90 min, 97%

NaOAc, HCrO3Cl.Pyr

CH2Cl2

RT, 2 h, 87%

NaH, (EtO)2P(O)CH2CO2Et

DME

RT, 3 h, 76%

See the Horner-Wadsworth-Emmons Reaction

Sealed tube

PhMe

245 °C, 30 h, 97%

See the Ene Reaction

LiAlH4

Et2O

RT to Reflux, 5 h, 90%

H2Cr2O7.2Pyr

4 Å MS

AcOH, CH2Cl2

0 °C to RT, 50 min, 82%

DMSO, NaH, TMSI

THF

0 °C to RT, 2 h, 61%

See the Johnson-Corey-Chaykovsky Reaction

TiCl4

CH2Cl2

-78 °C, 60 min, 72%

See the Hosomi-Sakurai Reaction

HCrO3Cl.Pyr

CH2Cl2

RT, 90 min, 70%

O2, CuCl2, PdCl2

DMF, H2O

RT to 57 °C, 4.5 h, 77%

See the Wacker Oxidation

KOH

EtOH, H2O

55 °C, 90 min, 40%

See the Aldol Condensation

H2, Pt/C

1 atm

EtOAc

RT, 60 min, 98%

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Remaining...

14% (5 step)

"See: J. Am. Chem. Soc. 1981, 103, 2744 and Tetrahedron Lett. 1976, 17, 195."