ETHYL4-IODOBUTYRATE

In a 100 ml round bottom flask, ethyl4-bromobutyrate (6.0 ml, 40.2 mmol: 1H NMR (300 MHz, CDCl3) δ 4.14(q, J = 7.2 Hz, 2H), 3.47 (t, J = 6.5 Hz, 2H), 2.49 (t, J = 7.2 Hz, 2H), 2.17(m, 2H), 1.26 (t, J = 7.1 Hz, 3H).) was dissolved in 40 ml acetone. Potassium iodide (13.35 g, 80.4 mmol, 2.0 equiv.) was added, a reflux condenser was attached, and the reaction was heated at reflux for 12h. Thesolution was cooled, filtered through a course fritted funnel, and concentrated in vacuo. The resultingyellow oil with fine particulates was taken up in ca 50 ml of 1:1 Hex:Et2O and filtered through neutralaluminum to remove color. After flushing with an additional 100 ml 1:1 Hex:Et2O, the solution wasconcentrated to yield 8.44 g (87percent) of ethyl 4-iodobutyrate 12. 1H NMR (300 MHz, CDCl3) δ 4.14 (q, J =7.2 Hz, 2H), 3.24 (t, J = 6.8 Hz, 2H), 2.44 (t, J = 7.1 Hz, 2H), 2.13 (m, 2H), 1.26 (t, J = 7.2 Hz, 3H). A 50ml Schlenk flask was flame dried under vacuum, cooled to 23 °C, and charged with ethyl 4-iodobutyrate(8.4 g, 34.7 mmol) and copper(I) iodide (10 mg, 0.05 mmol). After sealing with a greased ground glassstopper, the flask was evacuated and refilled with Ar. The stopper was replaced with a rubber septum andneat diethyl zinc (14 ml, 137 mmol, 4 equiv) was added via syringe. The reaction was heated at 40 °C for12 h. The excess diethyl zinc and ethyl iodide were removed under vacuum for 2 h into a trap withmethanol cooled to -78 °C with dry ice and acetone. (CAUTION: A trap cooled with liquid nitrogeneasily clogs so dry ice/acetone cooling is preferred. Methanol quenches the excess diethyl zinc, but careshould be taken when cleaning the trap as some diethyl zinc may remain.) After backfilling with Ar, THF(5 ml) was added to the reaction vessel and heated at 40 °C for 1 h under Ar. The reaction vessel wasevacuated for 1 h. This step was repeated another two times. After cooling to 23 °C, the generated bis(4-ethoxy-4-oxobutyl)zinc was diluted with 15 ml of THF and this solution was used directly in thedesymmetrization reaction.

Molecular Weight:242.05
XLogP3:2.1
Hydrogen Bond Acceptor Count:2
Rotatable Bond Count:5
Exact Mass:241.98038
Monoisotopic Mass:241.98038
Topological Polar Surface Area:26.3
Heavy Atom Count:9
Complexity:83.1
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes