THE SYNTHESIS OF [BIS(TRIFLUOROMETHYL)AMINO-OXY]-SUBSTITUTED BROMOALKANES AND THEIR CONVERSION INTO GRIGNARD-REAGENTS

Reaction of the nitroxide (CF3)(2)NO. (1) with the bromoalkanes RBr (R=Me, Et and Pr-n) (1:1 molar ratio) gives the compounds (CF3)(2)NOCH2Br (4a) (69%), (CF3)(2)NOCHBrMe (4b) (93%)+ (CF3)(2)NOCHBrCH2ON(CF3)(2) (6) (6%) and (CF3)(2)NOCHBrEt (4c) (16%)+(CF3)(2)NOCHMeCH(2)Br (7) (76%)+(CF3)(2)NOCH(2)CHBrMe (8) (3%), respectively, together with the hydroxylamine (CF3)(2)NOH (3). Treatment of the sodium salt (CF3)(2)NONa (2) with the dibromoalkanes Br(CH2)(n)Br (n =2 and 3) (1:1 molar ratio) in diglyme affords mixtures of elimination and substitution products, i.e. H2C=CHBr+(CF3)(2)NOCH2CH2Br (9a)+(CF3)(2)NOCH2CH2ON(CF3)(2) (10a) (ratio 21:39:7) and (CF3)(2)NOCH2CH=CH2 (12)+(CF3)(2)NO(CH2)(3)Br (9b)+(CF3)(2)NO(CH2)(3)ON(CF3)(2) (10b) (ratio 22:43:9). The alpha-substituted compounds 4a and 4b do not form Grignard reagents in diethyl ether, those formed from the beta-substituted compounds 7 and 9a undergo elimination to give propene and ethene respectively, while that produced from the gamma-substituted compound 9b is stable at room temperature and reacts with the chlorosilane MeSiCl(3) to afford the compound (CF3)(2)NO(CH2)(3)SiCl(2)Me (20) (53%).