The coupling reaction of aryl iodides with terminal alkynes by using a catalyst system of CuI-PPhs in the presence of K2CO3 as base gives the corresponding arylated alkynes in excellent yields. Addition of PPh3 is essential for the reaction to proceed catalytically. Vinyl iodides also react smoothly with the alkynes to give enyne compounds with retention of the configurations. While DMF and DMSO can be used as solvents, DMSO is found to be effective for the reaction with aliphatic terminal alkynes. A reaction mechanism involving initial formation of copper acetylide species coordinated by PPh3 followed by reaction of aryl and vinyl iodides is proposed.
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