friedelcraftsnot

friedelcraftsnot - R H 2 Pd during section on carbonyls + R...

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Friedel-Crafts A) Alkylation Think of as discrete carbocation that can rearrange Cl AlCl 3 Cl AlCl 3 δ + δ− Cl AlCl 3 H Cl AlCl 3 could also be H 2 O a WEAK base will suffice HCl AlCl 3 Cl B) Acylation O O O O AlCl 3 R R H Cl R R acylium ion + Cl AlCl 3 O R
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Comparison of Acylation vs. Alkylation Acyl Group ~ deactivating: will only react once ~ no rearrangements Alkyl Group ~ activating: may react more than once to give disubstituted benzene ~ will rearrange to form most stable carbocation Acylation is more reliable in synthesis O O AlCl 3 + R better R Cl acyl ketone Note that acyl ketone can be reduced to alkyl benzene O R we'll talk more about this
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Unformatted text preview: R H 2 Pd during section on carbonyls + R Cl AlCl 3 R R R note: O R R H 2 nitro group is REDUCED to AMINE Pd NO 2 NH 2 Synthesis Examples (A) + Cl AlCl 3 + + (B) + Cl AlCl 3 O O H 2 Pd (B) is better Keep in Mind Note that the Lewis acid AlCl 3 can complex with certain functional groups and kill the reaction. H H NH 2 Cl AlCl 3 Al Cl Cl N aniline Strongly e- withdrawing substituents on benzene will deactivate ring and prevent Friedel-Crafts O R Cl NO 2 AlCl 3 Alkylation may yield unexpected products (and mixtures of products) by rearrangement N.R. H H Cl AlCl 3 Cl AlCl 3 H...
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friedelcraftsnot - R H 2 Pd during section on carbonyls + R...

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