08-15-04 23:56
No 525705
i'm curious to the possibility of synthesizing safrole from 1,3-benzodioxole and allyl bromide using the zinc method: Post 408642 (Kinetic: "Zinc promoted Friedel-Crafts acylation", Novel Discourse).
I knows alkylations can me done this way but I am unsure whether the double bond on the allyl bromide would in some way hinder the reaction.
Thanks.
(Stranger)
08-17-04 06:22
No 525888
First, you will not get only the isomer you desire, because AFAIK, the allyl chloride or bromide will also alkylate ortho to the methylenedioxy structure.
Second, using normal friedel-crafts methods will generate HBr acid, which will tend to add across the allyl double bond, and possible cause multiple alkylations and polymerization. There are ways around this:
Post 468541 (ning: "high-yielding OTC allylation of aromatics, anyone?", Chemistry Discourse) scrubs up HX with supported K2CO3
Post 515205 (psyloxy: "TsOH - best Friedel-Crafts catalyst ever ?!", Novel Discourse) uses tosic acid to catalyze the magical alkylation
anyhow, it's not so easy as it seems.
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