Palladium-Catalyzed Alkoxycarbonylation of (Z)-2-En-4-yn Carbonates Leading to 2,3,5-Trienoates
摘要:
Pd(0)-catalyzed carbonylation of (Z)-2-en-4-yn carbonates in the presence of a balloon pressure of CO in an alcohol donates vinylallenyl esters with an exclusively E-configuration and in high yields. The fact that no such reactivity could be observed with E-configured enyne carbonates may indicate that the reaction is promoted via the cooperative coordination of palladium with both alkynyl and carbonate moieties.
Palladium-Catalyzed Alkoxycarbonylation of (Z)-2-En-4-yn Carbonates Leading to 2,3,5-Trienoates
摘要:
Pd(0)-catalyzed carbonylation of (Z)-2-en-4-yn carbonates in the presence of a balloon pressure of CO in an alcohol donates vinylallenyl esters with an exclusively E-configuration and in high yields. The fact that no such reactivity could be observed with E-configured enyne carbonates may indicate that the reaction is promoted via the cooperative coordination of palladium with both alkynyl and carbonate moieties.
The Pd(II)-catalyzed one-pot tandem cyclization/alkylation reactions of enynoates with allylic alcohols have been demonstrated. In this reaction, an innovative protocol proceeded well through Pd-catalyzed intramolecular selective 6-endo cyclization, insertion of allylic alcohols into the Pd–C bond of vinylpalladium species generated in situ, and β-hydrogen elimination processes. This conversion provides
A Pd(II)-catalyzed mild and highly regioselective 6-endo cyclization/allylation reaction of enynoates with simple allylic alcohols has been developed. Under mild reaction conditions, the vinyl palladium species generated in situ after cyclization could insert C–C double bond of allylic alcohol through cross-coupling reaction and lead to the formation of allyl pyrone via β-OH elimination. This cascade
Preparation and decarboxylative rearrangement of (Z)-enyne esters
作者:Jacqueline C.S. Woo、Shawn D. Walker、Margaret M. Faul
DOI:10.1016/j.tetlet.2007.06.012
日期:2007.8
A method to assemble (Z)-enyne esters via palladium-catalyzed cross coupling reactions of enol tosylates is reported. A base-mediated one-pot decarboxylative rearrangement of the enynes to enones is described. The scope of this process is examined. (c) 2007 Elsevier Ltd. All rights reserved.
Research on a compact adsorption room air conditioner
作者:G.Z. Yang、Z.Z. Xia、R.Z. Wang、Daou Keletigui、D.C. Wang、Z.H. Dong、X. Yang
DOI:10.1016/j.enconman.2005.12.005
日期:2006.9
A novel compact adsorption room air conditioner with a cooling capacity of 1 kW has been designed, and two prototypes have been built. A two bed, continuous adsorption refrigeration cycle with heat recovery and mass recovery is adopted. Micropore spherical silica gel and water are selected as the working pair. A gravity heat pipe with methanol as working medium is designed to output the cooling. Experimental investigations have indicated that under typical air conditioning conditions, for the first prototype, a cooling capacity of 687 W and a COP (coefficient of performance) of 0.307 can be obtained. However, for the improved one, a cooling capacity of 790 W and a COP of 0.446 can be reached. It is also proved that the operating temperatures have strong influences on the performance. The designed room air conditioner can be driven by a low grade heat source (< 90 degrees C) and has small dimensions of 300 mm (depth), 500 mm (width) and 950 mm (height). (c) 2006 Elsevier Ltd. All rights reserved.