Claisen Condensation

Schematic representation of the Claisen Condensation.

Mechanism of the Claisen Condensation

Mechanism of the Claisen Condensation

Original publication	Ber. Dtsch. Chem. Ges.. 1887, 20, 651. J. Org. Chem.. 2014, 79, 6868.
Reviews	Comp. Org. Syn.. 1991, 2, 806. Org. React.. 1954, 8, 59. Org. React.. 1967, 15, 1.

Sample reactions

intermediate structure

intermediate structure

NaOEt

82 °C, 14 h, 63%

intermediate structure

intermediate structure

i-Pr2NLi, MeO2CCN

THF

-78 °C

intermediate structure

intermediate structure

NaOMe, HCO2Et

PhH

RT, 12 h

intermediate structure

intermediate structure

NaH, HCO2Et

THF

0 °C to RT, 3 h

intermediate structure

intermediate structure

NaOMe, HCO2Et

PhH

RT, 30 min, 94%

intermediate structure

intermediate structure

NaOMe, HCO2Et

PhH

RT, ON

intermediate structure

intermediate structure

i-Pr2NLi, CDI, MeOAc

THF

-78 to 0 °C, 4 h, 72% (2 steps)

intermediate structure

intermediate structure

TMS2NK, ClCO2Bn

THF

-78 °C, 6 h, 70%

intermediate structure

intermediate structure

i-Pr2NLi, MeO2CCN

HMPA, THF

-78 °C, 90 min, 89%

intermediate structure

intermediate structure

intermediate structure

i-Pr2NLi

Et2O

-78 °C, 2 h

intermediate structure

intermediate structure

NaH, HCO2Et

THF

RT, 14 h, 83%

intermediate structure

intermediate structure

KH, HCO2Me

THF

RT, 8 h

intermediate structure

intermediate structure

n-BuLi, MeCN

THF

-88 to -78 °C, 60 min, 93%

intermediate structure

intermediate structure

intermediate structure

NaH, HCO2Me

MeOH, THF

RT to 40 °C, 20 h, 100%

intermediate structure

intermediate structure

intermediate structure

NaOMe, HCO2Me

PhH

95%

intermediate structure

intermediate structure

intermediate structure

i-Pr2NLi

THF

-78 °C, 19 h, 72%

"The yield was 82 % brsm."

intermediate structure

intermediate structure

TMS2NLi

THF

Reflux, 30 min

intermediate structure

intermediate structure

NaH

PhH

81% (2 steps)

intermediate structure

intermediate structure

Na, HCO2Et

Et2O

100%

intermediate structure

intermediate structure

NaOEt, (CO2Et)2

PhH

RT, 4 h, 40%

intermediate structure

intermediate structure

i-Pr2NLi, EtOAc

Hexane(s), THF

-78 °C to RT, 55 min, 71%

intermediate structure

intermediate structure

NaH, EtOAc

PhMe

110 °C, 15 h

intermediate structure

intermediate structure

NaH

DME

Reflux, 17 h

intermediate structure

intermediate structure

NaH, HCO2Me

THF

0 °C, 17 h

intermediate structure

intermediate structure

intermediate structure

ClCO2Et, Et3N

THF

0 °C to RT, ON, 77%

intermediate structure

intermediate structure

NaH, MeOAc, ClCH2CO2Me

DMF

50-60 °C, 4.5 h, 55%

intermediate structure

intermediate structure

NaH, (CO2Me)2

DMF, MeOH

35-80 °C, , 44%

intermediate structure

intermediate structure

NaOMe, HCO2Et

PhH

0 °C to RT, 20 h, 97%

intermediate structure

intermediate structure

NaOMe, HCO2Et

PhH

RT, ON

intermediate structure

intermediate structure

intermediate structure

LDA

THF

-78 °C to RT, 8.5 h, 89%

intermediate structure

intermediate structure

H2O, HCl, NaH, n-BuLi

THF

-78 °C to Reflux, 42 h, 67%

intermediate structure