Reaction #2487406

Reaction equation

4-chlorobutanol

triethylamine

Cyclobut-1-enecarboxylic acid

oxalyl dichloride

cyclobut-1-enecarboxylic chloride

→

21

Yield 38.2%

Cyclobut-1-enecarboxylic acid 4-chloro-butyl ester

Yield 38.2%

Solvents

CH2Cl2

CH2Cl2

Conditions

Workup

1. 1
   TemperatureThe temperature of the solution was raised to rt
2. 2
   Otherto react for 1 h
3. 3
   OtherThe solvent was evaporated
4. 4
   workup.ADDITIONbefore being added to
5. 5
   workup.STIRRINGThe reaction mixture was stirred for 16 h at rt
6. 6
   ConcentrationThe CH2Cl2 solution was concentrated by rotary evaporation
7. 7
   Otherpurified by flash column chromatography (60% CH2Cl2/pentane)

Procedure

Cyclobut-1-enecarboxylic acid (2.04 mmol, 200 mg) was dissolved in 1.5 mL dry CH2Cl2. The solution was cooled to 0° C. and oxalyl dichloride (4.08 mmol, 345 μL) was added. The temperature of the solution was raised to rt, and the mixture was allowed to react for 1 h. The solvent was evaporated to generate a viscous oil. 4-chlorobutanol (1.36 mmol, 148 mg) and triethylamine (2.72 mmol, 379 μL) were dissolved in 1.0 mL dry CH2Cl2, and the solution was stirred at 0° C. for 45 min before being added to a vial containing cyclobut-1-enecarboxylic chloride. The reaction mixture was stirred for 16 h at rt. The CH2Cl2 solution was concentrated by rotary evaporation, and then purified by flash column chromatography (60% CH2Cl2/pentane) to yield 21 as a colorless oil (98 mg, 38%). 1H-NMR (500 MHz, CDCl3) δ 6.73 (s, 1H), 4.11 (t, J=6.0 Hz, 2H), 3.54 (t, J=6.0 Hz, 2H), 2.68 (t, J=6.0 Hz, 2H), 2.43 (m, 2H), 1.81 (m, 4H). 13C NMR (100 MHz, CDCl3) δ 162.27, 146.69, 138.71, 63.31, 44.58, 29.31, 29.20, 27.20, 26.20.

Source