A synthesis of trifluoromethyl-substituted naphthalenes
作者:John M Mellor、Afaf H El-Sagheer、Ezz El-Din M Salem
DOI:10.1016/s0040-4039(00)01254-5
日期:2000.9
Alkyl and aryl Grignard reagents add to 1-(3,4-dihydro-2H-5-pyranyl)-2,2,2-trifluoro-1-ethanone by 1,4-addition, but benzyl Grignard reagents react in good yield by 1,2-addition. Dehydration of the resulting alcohols affords intermediate dienes, which readily undergo cyclisation to give substituted trifluoromethylnaphthalenes. Addition to other trifluoromethylketones permits access to a range of novel fluorinated naphthalenes and benzenes. (C) 2000 Published by Elsevier Science Ltd.
Reactions of 5-trifluoroacetyl-3,4dihydro-2H-pyran with zinc reagents
One pot reaction of 5-trifluoroacetyl-3,4-dihydro-2H-pyran with alkyl bromides Rbr in the presence of zinc powder gave the corresponding alcohol (CH2)(3)OCH=CC(R)(CF3)OH (R: CH2CO2Me, 3a; CH2=CHCH2- 3b); 3a readily hydrolysed to the corresponding carboxylic acid under dilute acidic conditions, intramolecular cycle addition of this acid afforded a bicycle lactone. (C) 1999 Elsevier Science S.A. All rights reserved.