The First Regioselective Hydroformylation of Acetylenic Thiophenes Catalyzed by a Zwitterionic Rhodium Complex and Triphenyl Phosphite
作者:Bernard G. Van den Hoven、Howard Alper
DOI:10.1021/jo9912653
日期:1999.12.1
The hydroformylation of acetylenic thiophenes is readily accomplished by using the zwitterionic rhodium catalyst (eta(6)-C6H5BPh3)-Rh+(1,5-COD) and triphenyl phosphite in the presence of CO and H-2. This catalytic system affords, as the major product, the alpha,beta-unsaturated aldehyde with the aldehyde and thiophene attached to the same olefin carbon atom. Assistance of sulfur from the heterocycle provides excellent regioselectivity and yields when the acetylenic unit is a propargyl ether or ester, phenylacetylene, or an enyne.
Butenolide Synthesis from Functionalized Cyclopropenones
作者:Sean S. Nguyen、Andrew J. Ferreira、Zane G. Long、Tyler K. Heiss、Robert S. Dorn、R. David Row、Jennifer A. Prescher
DOI:10.1021/acs.orglett.9b03298
日期:2019.11.1
A general method to synthesize substituted butenolides from hydroxymethylcyclopropenones is reported. Functionalized cyclopropenones undergo ring-opening reactions with catalytic amounts of phosphine, forming reactive ketene ylides. These intermediates can be trapped by pendant hydroxy groups to afford target butenolide scaffolds. The reaction proceeds efficiently in diverse solvents and with low catalyst