Oligomerization and hydroamination of terminal alkynes promoted by the cationic organoactinide compound [(Et₂N)₃U][BPh₄]

TY - JOUR

T1 - Oligomerization and hydroamination of terminal alkynes promoted by the cationic organoactinide compound [(Et2N)3U][BPh4]

AU - Wang, Jiaxi

AU - Dash, Aswini Kumar

AU - Kapon, Moshe

AU - Berthet, Jean Claude

AU - Ephritikhine, Michel

AU - Eisen, Moris S.

PY - 2002/12/2

Y1 - 2002/12/2

N2 - The three ancillary amido moieties in the cationic complex [(Et2N)3U][BPh4] are highly reactive and are easily replaced when the complex is treated with primary amines. The reaction of [(Et2N)3U][BPh4] with excess tBuNH2 allows the formation of the cationic complex [(tBuNH2)3(tBu-NH)3U][BPh4]. X-ray diffraction studies on the complex indicate that three amido and three amine ligands are arranged around the cationic metal center in a slightly distorted octahedral mer geometry. The cationic complex reacts with primary alkynes in the presence of external primary amines to primarily afford the unexpected cis dimer and, in some cases, the hydroamination products are obtained concomitantly. The formation of the cis dimer is the result of an envelope isomerization through a metal - cyclopropyl cationic complex. In the reaction of the bulkier alkyne tBuC≡CH with the cationic uranium complex in the presence of various primary amines, the cis dimer, one trimer, and one tetramer are obtained regioselectively, as confirmed by deuterium labeling experiments. The trimer and the tetramer correspond to consecutive insertions of an alkyne molecule into the vinylic CH bond trans to the bulky tert-butyl group. The reaction of (TMS)C≡CH with the uranium catalyst in the presence of EtNH2 followed a different course and produced the gem dimer along with the hydroamination imine as the major product. However, when other bulkier amines were used (iPrNH2 or tBuNH2) both hydroamination isomeric imines Z and E were obtained. During the catalytic reaction, the E (kinetic) isomer is transformed into the most stable Z (thermodynamic) isomer. The unique reactivity of the alkyne (TMS)C≡CH with the secondary amine Et2NH is remarkable because it afforded the trans dimer and the corresponding hydroamination enamine. The latter probably results from the insertion of the alkyne into a secondary metalamide bond, followed by protonolysis.

AB - The three ancillary amido moieties in the cationic complex [(Et2N)3U][BPh4] are highly reactive and are easily replaced when the complex is treated with primary amines. The reaction of [(Et2N)3U][BPh4] with excess tBuNH2 allows the formation of the cationic complex [(tBuNH2)3(tBu-NH)3U][BPh4]. X-ray diffraction studies on the complex indicate that three amido and three amine ligands are arranged around the cationic metal center in a slightly distorted octahedral mer geometry. The cationic complex reacts with primary alkynes in the presence of external primary amines to primarily afford the unexpected cis dimer and, in some cases, the hydroamination products are obtained concomitantly. The formation of the cis dimer is the result of an envelope isomerization through a metal - cyclopropyl cationic complex. In the reaction of the bulkier alkyne tBuC≡CH with the cationic uranium complex in the presence of various primary amines, the cis dimer, one trimer, and one tetramer are obtained regioselectively, as confirmed by deuterium labeling experiments. The trimer and the tetramer correspond to consecutive insertions of an alkyne molecule into the vinylic CH bond trans to the bulky tert-butyl group. The reaction of (TMS)C≡CH with the uranium catalyst in the presence of EtNH2 followed a different course and produced the gem dimer along with the hydroamination imine as the major product. However, when other bulkier amines were used (iPrNH2 or tBuNH2) both hydroamination isomeric imines Z and E were obtained. During the catalytic reaction, the E (kinetic) isomer is transformed into the most stable Z (thermodynamic) isomer. The unique reactivity of the alkyne (TMS)C≡CH with the secondary amine Et2NH is remarkable because it afforded the trans dimer and the corresponding hydroamination enamine. The latter probably results from the insertion of the alkyne into a secondary metalamide bond, followed by protonolysis.

KW - Alkynes

KW - Dimerization

KW - Homogeneous catalysis

KW - Hydroamination

KW - Uranium

UR - http://www.scopus.com/inward/record.url?scp=0037011064&partnerID=8YFLogxK

U2 - 10.1002/1521-3765(20021202)8:23<5384::AID-CHEM5384>3.0.CO;2-X

DO - 10.1002/1521-3765(20021202)8:23<5384::AID-CHEM5384>3.0.CO;2-X

M3 - 文章

C2 - 12561310

AN - SCOPUS:0037011064

SN - 0947-6539

VL - 8

SP - 5384

EP - 5396

JO - Chemistry - A European Journal

JF - Chemistry - A European Journal

IS - 23

ER -