Cornforth reagent → (E)-Hexadec-2-enal

HRID 1086006Notes

Reaction equation

HRID 1086006 reaction equation
[Cr](O[Cr]([O-])(=O)=O)([O-])(=O)=O.[NH+]1C=CC=CC=1.[NH+]1C=CC=CC=1.[CH2:22]([OH:38])/[CH:23]=[CH:24]/[CH2:25][CH2:26][CH2:27][CH2:28][CH2:29][CH2:30][CH2:31][CH2:32][CH2:33][CH2:34][CH2:35][CH2:36][CH3:37]>ClCCl>[CH:22](=[O:38])/[CH:23]=[CH:24]/[CH2:25][CH2:26][CH2:27][CH2:28][CH2:29][CH2:30][CH2:31][CH2:32][CH2:33][CH2:34][CH2:35][CH2:36][CH3:37]

Participants

4

Reactant 2

HCID 2724130Cornforth reagentHCID 5362706(E)-Hexadec-2-en-1-ol

Product 1

HCID 5280541(E)-Hexadec-2-enalYield 75%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To a stirred suspension of 60.6 g (0.161 mol) pyridinium dichromate in 100 mL of dichloromethane was added 25.7 g (0.107 mol) of trans-2-hexadecenol. After 4 h at 25° C., the mixture was filtered (through Celite diatomaceous earth) and the resulting brown solution refiltered through Florisil, an activated magnesium silicate in the form of hard, porous, stable, white granules that are free from dusting sold by Floridin Co. The colorless solution obtained was concentrated in vacuo to 21.8 g (86%) of a white solid. Distillation (90-100° C./0.40-0.45 torr) provided 19.1 g (75%) of pure trans-2-hexadecenal as a white waxy solid. IR (thin film as melt) 2920, 2850, 1695, 1465, 975 cm-1 ; 1H NMR (CDCl3, 300 MHz) δ 9.53 (d, 1, J=6.7 Hz, CHO), 6.88 (overlapping dt. 1, J=15.7, 6.7 Hz, OHCCH=), 1.53 (m, 2CH2CH3), 1.1-1.2 (m, 20, CH2CH2CH2), 0.90 (t, 3, J=7 Hz, CH2CH3). Rf (15% ethyl acetate:hexanes): trans-2-hexadecenol, 0.19 trans-2-hexadecenal, 0.44. MS(FD) m/e 238 (M+).

Workup

  1. filtrationthe mixture was filtered (through Celite diatomaceous earth)
  2. customThe colorless solution obtained
  3. concentrationwas concentrated in vacuo to 21.8 g (86%) of a white solid
  4. distillationDistillation (90-100° C./0.40-0.45 torr)

Sources & evidence

ORD record
ord-84278eda96424bf191448e417c5ca717
Source dataset
uspto-grants-1991_04
Patent number
US05012000

Reaction notes

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