The Barbier‐type allylation of aldehydes and ketones can be carried out with both unsubstituted and γ‐substituted allyl bromides using only a catalytic amount (0.1 equiv.) of In metal in [bmim][Br].
Effect of InCl 3 on the addition of Grignard reagents to α,β-unsaturated carbonyl compounds
作者:Brian G. Kelly、Declan G. Gilheany
DOI:10.1016/s0040-4039(01)02263-8
日期:2002.1
Control of 1,2- versus 1,4-addition of organometallic reagents to enones remains a long-standing problem. There is still no satisfactory 1,2-directing agent comparable to the 1,4-directing effect of copper salts. We report that the presence of just 5 mol% indium(III) chloride can significantly alter the amount of 1,2-product formed in these reactions.
The π-allyilanthanoidatecomplex (1), which was prepared in situ from tetra-allyltin, the lanthanoid trichloride, and n-butyl-lithium in tetrahydrofuran (THF), reacts smoothly with α,β-unsaturatedcarbonylcompounds (3)–(11) with a high degree of 1,2-regioselectivity to give 3-hydroxy-1, 5-dienes (12)–(20) in good to excellent yields.
Tandem anionic oxy‐Coperearrangement/radical oxygenation reactions provide δ,ϵ‐unsaturated α‐(aminoxy) carbonyl compounds, which serve as convenient precursors to diverse compound classes. Functionalized carbocycles are accessible by very rare all‐carbon 5‐endo‐trig cyclizations, but also common 5‐exo‐trig radical cyclizations, based on the persistent radical effect. The tandem reactions can be further
Ceric(IV) Ammonium Nitrate: A Novel Reagent for the Synthesis of Homoallyl Alcohols
作者:J. S. Yadav、B. V. S. Reddy、A. D. Krishna、K. Sadasiv、Ch. Janardhana Chary
DOI:10.1246/cl.2003.248
日期:2003.3
allylation of aldehydes with allyltributylstannane using a catalytic amount of ceric ammonium nitrate in acetonitrile under mild and neutral conditions to afford the corresponding homoallyl alcohols in excellent yields with high chemoselectivity. Allylation of ketones has also been achieved with tetraallytin under similar reaction conditions.