Novel generation ponytails in fluorous chemistry: Syntheses of primary, secondary, and tertiary (nonafluoro- tert-butyloxy)ethyl amines

Abstract

(Nonafluoro- tert-butyloxy)ethyl tosylate 4 was prepared in 65% yield from nonafluoro- tert-butanol 1 using commercially available reagents. Further reaction of 4 with HNR 1R 2 (R 1 = R 2 = H, CH 3; R 1 = H, R 2 = CH 3, (CH 2) 3C 8F 17, CH 2CH 2OC(CF 3) 3) affords the appropriate (CF 3) 3COCH 2CH 2NR 1R 2 amines in 20–69% yields. Improved overall yields of [(CF 3) 3COCH 2CH 2] 3− n NR n to 1 were obtained by the reaction of (CF 3) 3CONa 2 and (XCH 2CH 2) 3− n NR n (X = Cl, n = 0, 1, 2, R = CH 3; X = CH 3SO 2O, n = 1, R = CH 3SO 2) nitrogen mustards and a similar reactive β-substituted ethyl amine. The title amines are mobile colorless liquids and volatile with steam. The bulky fluorous ponytail (CF 3) 3CO(CH 2) 2 displays high acidic stability and increases fluorous character almost as much as the classical straight-chain C 8F 17(CH 2) 3 ponytail.