Diisopropylamine → Cyclododeca-4,8-diene-1-carbaldehyde

Temperature

-30 °C

i-Pr2NH [80 g; 0.79 mol] was added to tetrahydrofuran (THF) (100 ml), cooled to −30° C., and n-BuLi [40 ml of 2.5 M, 0.1 mol] added dropwise by syringe, under N2. (Trimethylsilyl)diazomethane (TMSCHN2) [50 ml; 1.9 M in hexane; 0.095 mol] was added dropwise to this lithium diisopropylamide (LDA) solution at −70° C. After complete addition, a solution of 4,8-cyclododecadien-1-one [14.2 g; 0.08 mol] in anhydrous THF (50 ml) was added, and the reaction mixture allowed to stir for 1 hour at −70° C., then allowed to reach ambient temperature. It was, subsequently, refluxed for 3 hours. Most of the THF was removed in vacuo, Et2O (300 ml) was added, and the reaction mixture poured into ice-water. After extraction into Et2O, the solvent was removed, the residue redissolved in ethyl acetate (300 ml), and silica gel (100 g) added, together with H2O (1 ml). The mixture was stirred overnight under N2, the mixture concentrated in vacuo, then loaded onto a short silica column. Flash chromatography using a mixture of hexane (90%) and Et2O (10%) as eluent, gave 4,8-cyclododecadiene carboxaldehyde (QRM 2815) as a colourless oil (14.0 g).

1. additionAfter complete addition
2. customto reach ambient temperature
3. temperaturesubsequently, refluxed for 3 hours
4. customMost of the THF was removed in vacuo, Et2O (300 ml)
5. additionwas added
6. additionthe reaction mixture poured into ice-water
7. extractionAfter extraction into Et2O
8. customthe solvent was removed
9. dissolutionthe residue redissolved in ethyl acetate (300 ml)
10. additionsilica gel (100 g) added, together with H2O (1 ml)
11. stirringThe mixture was stirred overnight under N2
12. concentrationthe mixture concentrated in vacuo
13. additiona mixture of hexane (90%) and Et2O (10%) as eluent

ORD record

ord-370851130d164e51921f42ae0c6a57fa

Source dataset

uspto-grants-2003_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06551988B1