When 3-fluoro- and 3-chloro-1,2-didehydrobenzenes are generated in the presence of 2-(trimethylsilyl)furan, two regioisomeric cycloadducts are formed in a 1:2 ratio. However, regioselectivity can be installed by fitting one bulky trimethylsilyl group into sterically crit. positions of each of the two reaction components. Thus 3-fluoro-6-trimethylsilyl-1,2-didehydrobenzene and 2-(trimethylsilyl)furan give one cycloadduct exclusively. In this way, the Diels-Alder reaction between suitably adorned arynes and similarly designed furans can open an entry to naphthalene derivs. that have unprecedented substituent patterns that qualify them as building blocks for pharmaceutical or agricultural research. The acid-catalyzed isomerization of model 1,4-epoxy-1,4-dihydronaphthalenes, the aryne/furan cycloadducts, exhibits unexpected effects on rates and regioselectivity. [on SciFinder (R)]
Title
Fluoronaphthalene building blocks via arynes: A solution to the problem of positional selectivity
Published in
European Journal of Organic Chemistry
Issue
20
Pages
4401-4405
Date
2005
Note
CAN 144:69609 25-24 Benzene, Its Derivatives, and Condensed Benzenoid Compounds Institute of Chemical Sciences and Engineering,Ecole Polytechnique Federale (BCh),Lausanne,Switz. Journal 1434-193X written in English. 871824-08-7P; 871824-09-8P Role: PNU (Preparation, unclassified), PREP (Preparation) (failed prepn. of trimethylsilyl fluoronaphthols via acid-catalyzed ring-opening of 1,4-epoxy-1,4-dihydro-5-fluoro-8-(trimethylsilyl)naphthalene); 871824-06-5P; 871824-07-6P Role: PNU (Preparation, unclassified), PREP (Preparation) (failed prepn. of trimethylsilyl naphthols via acid-catalyzed ring-opening of 1,4-epoxy-1,4-dihydro-5-(trimethylsilyl)naphthalene); 871824-01-0P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (prepn. of fluoronaphthalene derivs. via regioselective Diels-Alder cycloaddns. of arynes and furans, and failed reactant of acid-catalyzed ring-opening); 75-77-4 (Chlorotrimethylsilane); 110-00-9 (Furan); 372-18-9 (1,3-Difluorobenzene); 462-06-6 (Fluorobenzene); 541-73-1 (1,3-Dichlorobenzene); 110407-59-5 Role: RCT (Reactant), RACT (Reactant or reagent) (prepn. of fluoronaphthalene derivs. via regioselective Diels-Alder cycloaddns. of arynes and furans, and reaction rates and regioselectivity of acid-catalyzed ring-opening of epoxynaphthalene derivs.); 1578-33-2P (2-Trimethylsilylfuran); 1842-26-8P; 731799-14-7P; 871824-00-9P; 871824-05-4P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (prepn. of fluoronaphthalene derivs. via regioselective Diels-Alder cycloaddns. of arynes and furans, and reaction rates and regioselectivity of acid-catalyzed ring-opening of epoxynaphthalene derivs.); 90-15-3P (1-Naphthol); 61761-32-8P; 134965-26-7P; 134965-27-8P; 383155-01-9P; 871824-02-1P; 871824-03-2P; 871824-04-3P Role: SPN (Synthetic preparation), PREP (Preparation) (prepn. of fluoronaphthalene derivs. via regioselective Diels-Alder cycloaddns. of arynes and furans, and reaction rates and regioselectivity of acid-catalyzed ring-opening of epoxynaphthalene derivs.); 573-57-9 Role: RCT (Reactant), RACT (Reactant or reagent) (ref. compd. to calc. reaction rates of acid-catalyzed ring-opening of epoxynaphthalene derivs.)
Record creation date
2006-03-03
