Wittig rearrangement of lithiated allyl aryl ethers: a mechanistic study

A -75 DegC, alpha-lithiated allyl Ph ether undergoes mainly the Wittig rearrangement to afford, after acidic hydrolysis, 1-phenyl-2-propen-1-ol as the main product. A second metalation taking place at one of the ortho positions is the sole competing side reaction. Both, the significant decrease of the isomerization rate upon the introduction of a tert-Bu substituent in the para position of the arom. ring and the complete absence of rearrangement products suggest an intramol. addn./elimination process bringing about the aryl migration. The first step, a nucleophilic attack of the alpha- to the ipso-carbon atom generates a spiro-connected oxiranylidene-cyclohexadienyllithium species. This short-lived intermediate collapses to the final product, a lithium alkoxide, by the nucleofugal departure of the oxygen atom which simultaneously binds the metal atom. [on SciFinder (R)]


Published in:
European Journal of Organic Chemistry, 19, 4393-4397
Year:
2006
Keywords:
Note:
CAN 146:27372
22-6
Physical Organic Chemistry
Faculte des Sciences,Universite de Lausanne,Lausanne,Switz.
Journal
1434-193X
written in English.
1746-13-0 (Allyl phenyl ether) Role: CPS (Chemical process), PEP (Physical, engineering or chemical process), RCT (Reactant), PROC (Process), RACT (Reactant or reagent) (Wittig rearrangement; mechanistic study of the Wittig rearrangement of lithiated allyl aryl ethers); 24806-16-4P (Allyl 4-tert-butylphenyl ether) Role: CPS (Chemical process), PEP (Physical, engineering or chemical process), RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), PROC (Process), RACT (Reactant or reagent) (Wittig rearrangement; mechanistic study of the Wittig rearrangement of lithiated allyl aryl ethers); 106-95-6 (Allyl bromide) Role: RCT (Reactant), RACT (Reactant or reagent) (allylation of 4-tert-butylphenol; mechanistic study of the Wittig rearrangement of lithiated allyl aryl ethers); 98-54-4 (4-tert-Butylphenol) Role: RCT (Reactant), RACT (Reactant or reagent) (allylation; mechanistic study of the Wittig rearrangement of lithiated allyl aryl ethers); 104-53-0 (3-Phenylpropanal) Role: RCT (Reactant), RACT (Reactant or reagent) (enolization/trapping; mechanistic study of the Wittig rearrangement of lithiated allyl aryl ethers); 19917-00-1P; 66323-99-7P; 915129-35-0P; 915129-36-1P; 915129-37-2P Role: BYP (Byproduct), PREP (Preparation) (mechanistic study of the Wittig rearrangement of lithiated allyl aryl ethers); 863029-85-0 Role: RCT (Reactant), RACT (Reactant or reagent) (mechanistic study of the Wittig rearrangement of lithiated allyl aryl ethers); 83135-23-3P; 915129-34-9P Role: SPN (Synthetic preparation), PREP (Preparation) (mechanistic study of the Wittig rearrangement of lithiated allyl aryl ethers); 51425-56-0P Role: SPN (Synthetic preparation), PREP (Preparation) (prepn. but not obsd. in rearrangement reaction; mechanistic study of the Wittig rearrangement of lithiated allyl aryl ethers); 4393-06-0 (1-Phenyl-2-propen-1-ol) Role: RCT (Reactant), RACT (Reactant or reagent) (rearrangement/trapping; mechanistic study of the Wittig rearrangement of lithiated allyl aryl ethers)
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 Record created 2007-03-07, last modified 2018-01-27


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