Synthesis and reactivity of (C6F5)3B-N-heterocycle complexes.: 1.: Generation of highly acidic sp3 carbons in pyrroles and indoles

被引:56
作者
Guidotti, S
Camurati, I
Focante, F
Angellini, L
Moscardi, G
Resconi, L [1 ]
Leardini, R
Nanni, D
Mercandelli, P
Sironi, A
Beringhelli, T
Maggioni, D
机构
[1] Basell Polyolefins, Ctr Ric G Natta, I-44100 Ferrara, Italy
[2] Univ Bologna, Dipartimento Chim Organ A Mangini, I-40136 Bologna, Italy
[3] Univ Milan, Dipartimento Chim Inorgan Metallorgan & Anali, I-20133 Milan, Italy
[4] Univ Milan, Dipartimento Chim Sturtturale & Stereochim Inorga, I-20133 Milan, Italy
关键词
D O I
10.1021/jo020647x
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
reaction of pyrroles and indoles with B(C6F5)(3) and BCl3 produces 1:1 B-N complexes containing highly acidic sp(3) carbons, for example, N-[tris(pentafluorophenyl)borane]-5H-pyrrole (1) and N-[tris(pentafluorophenyl)borane] -3H-indole (2), that are formed by a new formal N-to-C hydrogen shift, the mechanism of which is discussed. With some derivatives, restricted rotation around the B-N bond and/or the B-C bonds was observed by NMR techniques, and some rotational barriers were calculated from experimental data. The acidity of the sp(3) carbons in these complexes is shown by their ability to protonate NEt3, with formation of pyrrolyl- and indolyl-borate ammonium salts. The driving force for this reaction is given by the restoration of the aromaticity of the heterocycle.
引用
收藏
页码:5445 / 5465
页数:21
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