O'Ferrall, Rory A. More; Larkin, Finbar; Walsh, Peter, Journal of the Chemical Society. Perkin transactions II, 1982, p. 1573 - 1580
作者:O'Ferrall, Rory A. More、Larkin, Finbar、Walsh, Peter
DOI:——
日期:——
Nucleophilic Addition to the η<sup>2</sup>-Alkyne Ligand in [CpFe(CO)<sub>2</sub>(η<sup>2</sup>-R−C⋮C−R)]<sup>+</sup>. Dependence of the Alkenyl Product Stereochemistry on the Basicity of the Nucleophile
acyl intermediates formed by initial nucleophilicaddition of basic nucleophiles at the CO ligand, (2) trans-alkenyl complexes 4 result from addition of less basic nucleophiles to the η2-alkyne ligand from the exo-side, and (3) the equilibrium of the CO addition governed by the basicity of the nucleophile is the key step of the diversity of the stereochemistry of the alkenyl products. Reactions of
阳离子η的反应2 -alkyne铁络合物,[FP(η 2 -Ph-C⋮CPH)] BF 4(1)[Fp的=(η 5 -C 5 H ^ 5)的Fe(CO)2 ],各种O-,N-和C-亲核试剂提供了包含Ph-C C-Ph键的产物。即,顺式- (3)和反式-烯基配合物(4),FP-C(PH)C(Ph) -组成女,和metallacycles中,Cp(CO)的Fe-C(PH)C(PH)-C(Ô )-Nu [在O(5)或Nu(6)]。的C的构造的晶体学测定用C部分3点4的产物分布的和分析表明,基本亲核试剂轴承烷基取代基产生的顺式烯基配合物(3)和/或所述metallacycles(5,6),而碱性较弱的带有芳基取代基的亲核试剂提供了反式-烯基配合物(4)。亲核试剂的产物分布与p K b值之间的相关性得出以下结论:(1)产物3,5,和6从由初始的亲核加成基本亲核试剂在CO的配体形成的酰基中间体出现,(
Alkali-metal-assisted transfer of the carbamate group from phosphocarbamates to alkyl halides: a new easy way to alkali-metal carbamates and to carbamate esters
作者:Michele Aresta、Eugenio Quaranta
DOI:10.1039/dt9920001893
日期:——
P(NR2)3, have been used as a source of carbamate groups in the reaction with alkyl halides, R′X, to afford carbamateesters. The reaction is mediated by alkali-metal halides, MY, and requires the presence of a suitable macrocyclic polyether (L). The overall reaction occurs in two steps: the carbamic group is first transferred to the alkali-metal cation to give a carbamate salt [ML][O2CNR2] which then reacts