Bh. Lipshutz et Mr. Wood, SPECTROSCOPIC STUDIES ON CYANOCUPRATE-CATALYZED 3-COMPONENT COUPLINGS- UNDERSTANDING THE CATALYTIC CYCLE, Tetrahedron letters, 35(35), 1994, pp. 6433-6436
Low temperature 1H NMR analysis of a reaction mixture containing a vin
ylic zirconocene, MeLi, Me(3)ZnLi, 20 mol % Me(2)Cu(CN)Li-2 and an eno
ne, reagents which together lead to the Michael delivery of a vinyl li
gand, reveals the presence of a zinc enolate, the species likely to be
responsible for the subsequent alkylation or aldol reaction as the fi
nal step in 3-component couplings.