Aldol additions of pinacolone lithium enolate with ketones: reactivities governed predominantly by field effects
作者:Goutam Das、Edward R. Thornton
DOI:10.1021/ja00057a012
日期:1993.2
The relative reactivities of representative α- and β-heterosubstituted acyclic, cyclic (five- and six-membered), and aromatic ketones with the lithiumenolate of pinacolone in diethyl ether at -78 o C were determined. The order of reactivitiesof monosubstituted acetones (MeCOCH 2 X) is X=Cl>OTBDMS>OMe>SMe>NMe 2 >CH 2 SM>H>Me and spans a range of 10 4
测定了代表性的 α- 和 β- 杂取代的无环、环状(五元和六元)和芳香酮与频哪酮的烯醇锂在 -78 o C 的二乙醚中的相对反应性。单取代丙酮 (MeCOCH 2 X) 的反应性顺序为 X=Cl>OTBDMS>OMe>SMe>NMe 2 >CH 2 SM>H>Me,范围为 10 4
The Zirconium Alkoxide-Catalyzed Aldol-Tishchenko Reaction of Ketone Aldols
作者:Christoph Schneider、Markus Hansch、Timo Weide
DOI:10.1002/chem.200400951
日期:2005.1
Evaluation of a broad range of metal alkoxides as catalysts and optimization of the reaction protocol led to a modified zirconium alkoxide catalyst with attenuated Lewis acidity and dichloromethane as solvent, which resulted in suppression of the undesired acyl migration to a large extent. Various ketone aldols have been prepared and subjected to the general process, giving rise to a broad range of differently
Synthesis and formal [4 + 2] cycloaddition reactions of vinylimido complexes of titanocene
作者:Kenneth M. Doxsee、Judah B. Farahi、Hakon Hope
DOI:10.1021/ja00023a042
日期:1991.11
Sources of the methylidene complex of titanocene, Cp2Ti = CH2, react with nitriles in the presence of donor ligands to afford vinylimido titanocene complexes. The vinylimido complexes react readily with ketones, nitriles, and imines, yielding products that retain the elements of the imido ligand. In no case are products of formal [2 + 2] metathesis obtained. Concerted or stepwise [4 + 2] cycloadditions are suggested as possible mechanisms for these coupling reactions.
Colonge; Grenet, Bulletin de la Societe Chimique de France, 1954, p. 1304,1307