Intramolecular Nucleophilic Substitution in a C₆F₅ Moiety Assisted by Antimony

Abstract

Antimony tris‐amides — (Et2N)3−nSb[N(C6F5)(2‐C5H4N)]n [n = 1 (3), 2 (4) or 3 (5)] — have been prepared by treatment of Sb(NEt2)3 (1) with stoichiometric amounts of (2‐C5H4N)(C6F5)NH (2). In contrast to amide 5, compounds 3 and 4 are unexpectedly unstable and react further to give the bis‐amido antimony fluorides [(2‐Et2N‐C6F4)(2‐C5H4N)N]Sb(F)[N(C2H5)2] (6) and [(2‐Et2N‐C6F4)(2‐C5H4N)N]Sb(F)[N(C6F5)(2‐C5H4N)] (7). The structure of 7 was confirmed by X‐ray diffraction studies. DFT calculations, which reproduce the principal features of compound 7’s geometry, have been used to explain the possible reaction pathway of this ortho‐directed metathetical fluoride‐amide exchange. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

ortho‐Directed Metathetical Fluoride/Amide Exchange in (Pentafluorophenyl)amides

“…The twofold excess of lithiated 2-pyridylamine per mol of C 6 F 6 is essential as product 1 is acidic enough to quench the nucleophile. (1) Treatment of Bi(NMe 2 ) 3 (2) with 3 equiv. of amine 1 in toluene and the reaction of lithium amide 4 with BiCl 3 (5) both afforded tris(amide) 2 in good yield [Equation (2)].…”

“…[18] We also used this reaction to prepare amine 1, although we modified the method according to Equation (1). The twofold excess of lithiated 2-pyridylamine per mol of C 6 F 6 is essential as product 1 is acidic enough to quench the nucleophile.…”

“…[1] Trivalent antimony compounds containing one or two NEt 2 groups are unexpectedly unstable, and they rearrange to give the bis(amido)antimony fluorides [SbF{N(C 6 F 5 )(2-C 5 H 4 N)} 2 ] and [(Et 2 N)SbF{N(C 6 F 5 )(2-C 5 H 4 N)}], in almost quantitative yield at room temperature within 21 d. [1] To the best of our knowledge no such intramolecular rearrangements have been reported previously except in a paper by Schrock et al, where a similar nucleophilic substitution product is reported in low yield in the reaction of Mo(NMe 2 ) 4 with (C 6 F 5 NHCH 2 CH 2 ) 2 NMe. [15] In order to gain further insight into the fluoride/amide metathesis assisted by antimony, and to expand the scope of this reaction, we report herein our investigation of the analogous transamination reactions of Bi(NMe 2 ) 3 (2) and [In-(NEt 2 ) 3 ] 2 (3) with C 6 F 5 NH(2-C 5 H 4 N) (1). The reactions of the lithium salt of amine 1, namely C 6 F 5 NLi(2-C 5 H 4 N) (4), with BiCl 3 (5), InCl 3 (6), Me 3 SbBr 2 (7), and Me 3 SbCl 2 (8) are also reported.…”

“…[13,14] Recently, we reported the reaction of Sb(NEt 2 ) 3 with C 6 F 5 (2-C 5 H 4 N)NH (1), which leads to the antimony tris-(amide)s [(Et 2 N) 2 Sb{N(C 6 F 5 )(2-C 5 H 4 N)}], [(Et 2 N)Sb{N-(C 6 F 5 )(2-C 5 H 4 N)} 2 ], and [Sb{N(C 6 F 5 )(2-C 5 H 4 N)} 3 ] with one, two, or three pentafluoro(2-pyridyl)anilido groups. [1] Trivalent antimony compounds containing one or two NEt 2 groups are unexpectedly unstable, and they rearrange to give the bis(amido)antimony fluorides [SbF{N(C 6 F 5 )(2-C 5 H 4 N)} 2 ] and [(Et 2 N)SbF{N(C 6 F 5 )(2-C 5 H 4 N)}], in almost quantitative yield at room temperature within 21 d. [1] To the best of our knowledge no such intramolecular rearrangements have been reported previously except in a paper by Schrock et al, where a similar nucleophilic substitution product is reported in low yield in the reaction of Mo(NMe 2 ) 4 with (C 6 F 5 NHCH 2 CH 2 ) 2 NMe. [15] In order to gain further insight into the fluoride/amide metathesis assisted by antimony, and to expand the scope of this reaction, we report herein our investigation of the analogous transamination reactions of Bi(NMe 2 ) 3 (2) and [In-(NEt 2 ) 3 ] 2 (3) with C 6 F 5 NH(2-C 5 H 4 N) (1).…”

Reaction of [In(NEt2)3]2 with N(CH2CH2NSiMe3H)3: Synthesis and Characterization of New Azaindatranes and Azaindocane

“…[16] However, as observed for azametallatranes, C-β as well as C-α atoms may occupy ''flap'' sites of the ''envelope''. [6,17] …”