Mild and Selective Activation and Substitution of Strong Aliphatic C-F Bonds

作者：Janjetovic Mario; Traeff Annika M; Hilmersson Goeran^*

来源：Chemistry - A European Journal, 2015, 21(9): 3772-3777.

DOI：10.1002/chem.201406097

• amines
• chemoselectivity
• fluorine
• lanthanum
• synthetic methods

A procedure for chemoselectively manipulating the strong aliphatic CF bond with direct transformation into a CN bond under mild conditions is reported. The activation and subsequent substitution of primary alkyl fluorides is mediated by La[N(SiMe3)(2)](3), and results in high to excellent yields of tertiary amines. The methodology displays high selectivity towards the C(sp(3))F bond, and a variety of secondary amines are applicable as nucleophiles. Mechanistic investigations reveal a reaction that is first order with respect to [La[N(SiMe3)(2)](3)], [(RRNH)-R-1-N-2], and [alkyl fluoride], and a 6-membered cyclic transition state is proposed. In addition, (HNMR)-H-1 spectroscopy shows that La[N(SiMe3)(2)](3) is the active species involved in the substitution and that protonolysis of the amine, yielding La[(NRR2)-R-1](3), lowers the reactivity.

• 出版日期2015-2-23