2-(Propan-2-yl)-5-(propan-2-ylidene)cyclopenta-1,3-diene → 1,3-Bis(1-methylethyl)-1,3- cyclopentadiene
Reaction equation
[CH:1]([C:4]1[CH:5]=[CH:6][C:7](=[C:9]([CH3:11])[CH3:10])[CH:8]=1)([CH3:3])[CH3:2].[H-].[H-].[H-].[H-].[Li+].[Al+3]>>[CH:9]([C:7]1[CH2:6][CH:5]=[C:4]([CH:1]([CH3:3])[CH3:2])[CH:8]=1)([CH3:11])[CH3:10]Participants
3
Procedure
Therefore, 1,3-diisopropylcyclopentadiene was selected as the starting point for the synthesis. Unfortunately, the reported syntheses of 1,3-diisopropylcyclopentadiene gave low yields since the final step was always separation of the 1,3 product from the 1,2 product. A more selective method was found by extension of work by Nile in which he prepared a number of 1,3 disubstituted cyclopentadienes using a fulvene route. Using this method, reaction of isopropylcyclopentadiene with acetone catalyzed by pyrrolidine gave the 3-isopropyl-6,6-dimethylfulvene. Subsequent reduction of the fulvene with LAH and hydrolysis provided 1,3-diisopropylcyclopentadiene, "iPr2Cp." ##STR10##
Sources & evidence
- ORD record
- ord-b93f0c2a40614c8eb4214f38816e3bae
- Source dataset
- uspto-grants-1998_01
- Patent number
- US05708101
Reaction notes
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