2-, 3-, and 4-(trifluoromethoxy)phenyllithiums: versatile intermediates offering access to a variety of new organofluorine compounds
Consecutive treatment of (trifluoromethoxy)benzene with sec-butyllithium and electrophilic reagents affords previously inaccessible ortho-substituted derivs. in generally excellent yields. 2-(Trifluoromethoxy)phenyllithium acts as the key intermediate. The 3- and 4-isomers can readily be generated from the corresponding 3- and 4-bromo precursors by halogen-metal interconversion with butyllithium or tert-butyllithium. Upon trapping of the 2-, 3- and 4-(trifluoromethoxy)phenyllithiums with 11 different electrophiles (B(OH)2, OH, Br, I, CH3, EtOH, CHO, COCOOEt, COCH2COOEt, COOH, CN) the expected products were formed in generally high yields (up to 95%). Only the attempted nucleophilic addn. of 2-(trifluoromethoxy)phenyllithium to oxirane did not succeed. This failure is tentatively attributed to a lowering of the nucleophilicity by fluorine-lithium interactions. Conformationally restricted analogs - i.e., 2,2-difluoro-1,3-benzodioxol-4-phenyllithium and its 5-fluoro- and 5-bromo-substituted congeners - did indeed react smoothly with oxirane, affording the adducts in ordinary yields. [on SciFinder (R)]
2001
4
691
695
CAN 134:295851 29-2 Organometallic and Organometalloidal Compounds Institut de Chimie organique de l'Universite,Lausanne-Dorigny,Switz. Journal 1434-193X written in English. 353-46-8; 367-46-4; 553-90-2 (Dimethyl oxalate); 1130-90-1 (1-Naphthyl cyanate); 33142-21-1 (Ethyl 2-chloro-3-oxopropionate); 334778-34-6; 334778-35-7; 334778-36-8 Role: RCT (Reactant), RACT (Reactant or reagent) (electrophilic addn. reaction of (trifluoromethoxy)phenyllithiums with electrophiles); 75-21-8 (Oxirane); 126120-85-2; 334778-42-6; 334778-43-7 Role: RCT (Reactant), RACT (Reactant or reagent) (nucleophilic addn. reaction of benzodioxoles with oxirane); 641631-96-1 (prepn. of); 330-12-1P; 332-25-2P; 659-28-9P; 705-44-2P; 706-27-4P; 1014-81-9P; 1979-29-9P; 32858-93-8P; 42908-77-0P; 52771-21-8P; 63968-85-4P; 64115-88-4P; 94651-33-9P; 103962-05-6P; 137218-27-0P; 139301-27-2P; 175278-00-9P; 175676-65-0P; 179113-90-7P; 196811-90-2P; 198206-33-6P; 252955-06-9P; 334778-37-9P; 334778-38-0P; 334778-39-1P; 334778-40-4P; 334778-41-5P; 642444-30-2P; 642447-55-0P; 642451-74-9P; 642459-94-7P Role: SPN (Synthetic preparation), PREP (Preparation) (prepn. of)
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