Ethyl Bromide → alpha-Tocopherol
Reaction equation
[CH3:1][C:2]1([CH2:16][CH2:17]Br)[CH2:11][CH2:10][C:9]2[C:4](=[C:5]([CH3:15])[C:6]([CH3:14])=[C:7]([OH:13])[C:8]=2[CH3:12])[O:3]1.C([Mg]Br)C.[Mg].BrCC.[CH3:27][CH:28]([CH2:32][CH2:33][CH2:34][CH:35]([CH3:42])[CH2:36][CH2:37][CH2:38][CH:39]([CH3:41])[CH3:40])[CH2:29][Mg]Cl>C1COCC1>[CH3:14][C:6]1[C:7]([OH:13])=[C:8]([CH3:12])[C:9]2[CH2:10][CH2:11][C@:2]([CH2:16][CH2:17][CH2:41][C@@H:39]([CH2:38][CH2:37][CH2:36][C@@H:35]([CH2:34][CH2:33][CH2:32][CH:28]([CH3:29])[CH3:27])[CH3:42])[CH3:40])([CH3:1])[O:3][C:4]=2[C:5]=1[CH3:15]Participants
Procedure
3.13 g (10 millimoles) of (2RS)-2,5,7,8-tetramethyl-6-hydroxy-2-(2-bromoethyl)-chroman were dissolved in 10 ml of absolute THF. A solution of ethyl-magnesium bromide which had been prepared by reacting 0.25 g (10.3 millimoles) of magnesium in 3 ml of THF with a solution of 1.1 g (10.0 millimoles) of bromoethane in 5 ml of THF and stirring for 1 hour at +40° C. was added dropwise to the above solution at -20° C. The resulting reaction mixture was stirred for 1 hour at -20° C. and then there were added to it the (2RS,6RS)-2,6,10-trimethyl-1-undecyl-magnesium chloride solution prepared in Example 2a, followed by 0.7 ml of an 0.5-molar solution of di-lithium tetrachlorocuprate in absolute THF. The batch was then stirred for 3 hours at -20° C. and 16 hours at room temperature. The reaction mixture was worked up as described in Example 1c and 3.7 g of α-tocopherol were isolated by bulb tube distillation at 220° C./0.2 mbar. This corresponds to a yield of 86% of theory.
Workup
- additionwas added dropwise to the above solution at -20° C
- customThe resulting reaction mixture
- stirringwas stirred for 1 hour at -20° C.
- stirringThe batch was then stirred for 3 hours at -20° C. and 16 hours at room temperature
Sources & evidence
- ORD record
- ord-004bfa9a73d544e9af9460e841fa595e
- Source dataset
- uspto-grants-1985_10
- Patent number
- US04550182
Reaction notes
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