Nickel-catalyzed addition of dimethylzinc to aldehydes across alkynes and 1,3-butadiene: an efficient four-component connection reaction.
In the presence of 10 mol % of Ni(acac)(2), four components comprising Me(2)Zn, alkynes, 1,3-butadiene, and carbonyl compounds combine in this order in 1:1:1:1 ratio to furnish (3E,6Z)-octadien-1-ols 1 in good yields. Similarly, the coupling reaction of Me(2)Zn, 1,omega-dienynes 5, and carbonyls furnishes 1-alkylidene-2-(4'-hydroxy-(1'E)-alkenyl)cyclopentanes and -cyclohexanes 6 and their oxygen and nitrogen heterocycle derivatives in good yield and an excellent level of 1,5-diastereoselectivity with respect to the cycloalkane methine carbon and the OH-bearing carbon of the C2 side chain. The reaction is completed in most cases within 1 h at room temperature under nitrogen, tolerates an ester, a hydroxy, an allyl and propargyl ethers, an allylamino, and a pyridyl functionalities, and accommodates a variety of aromatic and aliphatic alkynes and carbonyls (aldehydes and ketones).
Kimura
Masanari
M
Contribution from the Department of Applied Chemistry, Faculty of Engineering, Nagasaki University, 1-14 Bunkyo, Nagasaki 852-8521, Japan.
Ezoe
Akihiro
A
Mori
Masahiko
M
Tamaru
Yoshinao
Y