New Pathway to<i>C</i><sub>2</sub>‐Symmetric Atropoisomeric Bipyridine<i>N</i>,<i>N′</i>‐Dioxides and Solvent Effect in Enantioselective Allylation of Aldehydes
The [2+2+2] cyclotrimerization of 1,7,9,15-hexadecatetrayne with nitriles catalyzed by dicarbonylcyclopentadienylcobalt(I) opened a new pathway for the synthesis of C2-symmetrical bis(tetrahydroisoquinolines) that were used as starting material for the preparation of axially chiral bipyridine N,N′-dioxides. The N,N′-dioxides (1 mol%) were found to be highly catalytically active and enantioselective
Cross-Cyclotrimerization with Two Nitriles as a Synthetic Pathway to Unsymmetrically 3,3’-Disubstituted bis(Tetrahydroisoquinolines)
作者:Aneta Kadlčíková、Martin Kotora
DOI:10.3390/molecules14082918
日期:——
Microwave assisted CpCo(CO)2 catalyzed cross-cyclotrimerizations of 1,7,9,15-hexadecatetrayne with two different nitriles to give unsymmetrically substituted bis(tetrahydroisoquinolines) was studied. The reaction proceeded with a range of alkyl and aryl nitriles with reasonable isolated yields.
Abstractmagnified imageUnsymmetrically 3,3′‐substituted axially chiral bis(tetrahydroisoquinoline) N,N′‐dioxides can be prepared in just three steps. They exhibit unique catalytic activity (turnover frequency, enantioselectivity, substrate scope) in the asymmetric allylation of aromatic aldehydes (up to 96% ee). The product of the enantioselective allylation of benzaldehyde served as a building block for the preparation of an intermediate useful in the enantioselective synthesis of diospongines.
Zinkevich,E.P. et al., Journal of Organic Chemistry USSR (English Translation), 1966, vol. 2, p. 1982 - 1986
作者:Zinkevich,E.P. et al.
DOI:——
日期:——
Copper-Zeolites as Catalysts for the Coupling of Terminal Alkynes: An Efficient Synthesis of Diynes
作者:Philippe Kuhn、Aurélien Alix、Mayilvasagam Kumarraja、Benoit Louis、Patrick Pale、Jean Sommer
DOI:10.1002/ejoc.200800848
日期:2009.1
CuI-modified zeolites, especially CuI–USY, proved to be very efficient catalysts for the homocoupling of terminalalkynes. Such heterogeneous catalysts offer a very simple (no added ligand) and convenient synthesis of diynes, including carbohydrate derivatives. A strong influence of the zeolite pore size has been observed, high (quantitative) yields being obtained with zeolites having large internal