TY - JOUR
T1 - Cross dimerization of terminal alkynes catalyzed by [(Et2N) 3U][BPh4]
AU - Wang, Jiaxi
AU - Kapon, Moshe
AU - Berthet, Jean Claude
AU - Ephritikhine, Michel
AU - Eisen, Moris S.
N1 - Funding Information:
The research was supported by the Israel Science Foundation, administered by the Israel Academy of Sciences and Humanities under contract 83/01-1, by the fund for the promotion of research at the Technion, and by the Technion VPR fund. M.S.E. thanks the Humboldt Foundation for support during the preparation of this manuscript. J.W. thanks the Technion for a postdoctoral fellowship.
PY - 2002/5/30
Y1 - 2002/5/30
N2 - The cationic complex [(Et2N)3U][BPh4] reacts with a mixture of terminal alkynes inducing the synthesis of the cross dimerization products. For equimolar amounts of aliphatic alkynes ( iPrCCH, tBuCCH) the head-to-tail geminal dimer of iPrCCH and the geminal cross dimer resulting from the insertion of iPrCCH into the U-CCR (R=iPr, tBu) moiety are obtained. When a mixture of PhCCH is reacted with either iPrCCH or tBuCCH, different products are obtained depending on the molar ratio of the alkynes. The dimerization of iPrCCH with an excess of PhCCH produces the geminal head-to-tail cross dimer issued from the insertion of the aliphatic alkyne into the U-CCPh moiety, and the geminal dimer of PhCCH. Inverting the molar ratio of the alkynes and using the deuterium labeled aliphatic alkyne iPrCCD, the deuterated geminal head-to-tail cross dimer is obtained preferentially with small amounts of the deuterated head-to-tail dimer of iPrCCD. The mixture of tBuCCH and PhCCH is converted into the geminal head-to-tail cross dimer in good yield if the former alkyne is in large excess. The addition of external EtNH2 in the cross dimerization of iPrCCH with PhCCH induces a different chemoselectivity producing mainly the cis-dimer of PhCCH. The use of a bulky amine, tBuNH2, with tBuCCH causes the decomposition of the catalytic complex, forming the salt [tBuNH 3][BPh4]·tBuNH2.
AB - The cationic complex [(Et2N)3U][BPh4] reacts with a mixture of terminal alkynes inducing the synthesis of the cross dimerization products. For equimolar amounts of aliphatic alkynes ( iPrCCH, tBuCCH) the head-to-tail geminal dimer of iPrCCH and the geminal cross dimer resulting from the insertion of iPrCCH into the U-CCR (R=iPr, tBu) moiety are obtained. When a mixture of PhCCH is reacted with either iPrCCH or tBuCCH, different products are obtained depending on the molar ratio of the alkynes. The dimerization of iPrCCH with an excess of PhCCH produces the geminal head-to-tail cross dimer issued from the insertion of the aliphatic alkyne into the U-CCPh moiety, and the geminal dimer of PhCCH. Inverting the molar ratio of the alkynes and using the deuterium labeled aliphatic alkyne iPrCCD, the deuterated geminal head-to-tail cross dimer is obtained preferentially with small amounts of the deuterated head-to-tail dimer of iPrCCD. The mixture of tBuCCH and PhCCH is converted into the geminal head-to-tail cross dimer in good yield if the former alkyne is in large excess. The addition of external EtNH2 in the cross dimerization of iPrCCH with PhCCH induces a different chemoselectivity producing mainly the cis-dimer of PhCCH. The use of a bulky amine, tBuNH2, with tBuCCH causes the decomposition of the catalytic complex, forming the salt [tBuNH 3][BPh4]·tBuNH2.
KW - Alkynes
KW - Borate complex
KW - Cationic uranium complex
KW - Cross dimerization
KW - Dimerization
UR - http://www.scopus.com/inward/record.url?scp=1842473945&partnerID=8YFLogxK
U2 - 10.1016/S0020-1693(02)00798-3
DO - 10.1016/S0020-1693(02)00798-3
M3 - 文章
AN - SCOPUS:1842473945
SN - 0020-1693
VL - 334
SP - 183
EP - 192
JO - Inorganica Chimica Acta
JF - Inorganica Chimica Acta
ER -