Syntheses of Seven-Membered Rings: Ruthenium-Catalyzed Intramolecular [5+2] Cycloadditions
作者:Barry M. Trost、Hong C. Shen、Daniel B. Horne、F. Dean Toste、Bernhard G. Steinmetz、Christopher Koradin
DOI:10.1002/chem.200401065
日期:2005.4.8
The Ru-catalyzed intramolecular [5+2] cycloaddition of cyclopropylenynes is investigated with respect to the regio- and diastereoselectivity as well as the functional group compatibility of the reaction. Evidence for the mechanism as occurring through a ruthenacyclopentene intermediate is elucidated from 1) the study of the diastereoselectivity of the cycloaddition; 2) the effect of variation of substituents
Palladium-Catalyzed Double-Decarboxylative Addition to Pyrones: Synthesis of Conjugated Dienoic Esters
作者:Tapan Maji、Jon A. Tunge
DOI:10.1021/acs.orglett.5b02308
日期:2015.10.2
protocol has been developed utilizing pyrone as a C4 synthon. This palladium-catalyzed transformation difunctionalizes the pyrone moiety by in situ generation and activation of both the electrophile and nucleophile via a double decarboxylation pathway. Ultimately, allyl carbonates react smoothly with 2-carboxypyrone under mild reaction conditions to generate synthetically useful acyclic dienoic esters
Direct, Stereoselective Substitution in [Rh(CO)<sub>2</sub>Cl]<sub>2</sub>-Catalyzed Allylic Alkylations of Unsymmetrical Substrates
作者:Brandon L. Ashfeld、Kenneth A. Miller、Stephen F. Martin
DOI:10.1021/ol0496529
日期:2004.4.1
[Rh(CO)(2)Cl](2) has been found to possess the unusual property of catalyzing allylicalkylations of unsymmetrical allylic carbonates with high levels of regioselectivity to provide products arising from substitution at the carbon atom bearing the leaving group, irrespective of the structure of the starting carbonate. The substitution reaction occurs with retention of stereochemistry at the reacting
[Rh(CO)<sub>2</sub>Cl]<sub>2</sub>-Catalyzed Domino Reactions Involving Allylic Substitution and Subsequent Carbocyclization Reactions
作者:Brandon L. Ashfeld、Kenneth A. Miller、Anna J. Smith、Kristy Tran、Stephen F. Martin
DOI:10.1021/ol0504300
日期:2005.4.14
[reaction: see text] Three novel domino reaction processes have been discovered and developed that employ the regioselective and stereoselective [Rh(CO)(2)Cl](2)-catalyzed alkylations of allylic trifluoroacetates with alpha-substituted sodiomalonates followed by an intramolecular Pauson-Khandannulation, a [5 + 2] cycloaddition, or a cycloisomerization. A unique aspect of the methodology is that a
Features and Applications of [Rh(CO)<sub>2</sub>Cl]<sub>2</sub>-Catalyzed Alkylations of Unsymmetrical Allylic Substrates
作者:Brandon L. Ashfeld、Kenneth A. Miller、Anna J. Smith、Kristy Tran、Stephen F. Martin
DOI:10.1021/jo701290b
日期:2007.11.1
A novel regio- and stereoselective [Rh(CO)2Cl]2-catalyzed allylic alkylation of unsymmetrical allylic carbonates was discovered. The regioselectivity of the reaction favors product ratios in which substitution occurs at the carbon bearing the leaving group. When an enantiomerically enriched carbonate (≥99% ee) was examined, the Rh(I)-catalyzed allylic alkylation proceeded stereoselectively to provide