Tandem Addition β-Lithiation−Alkylation Sequence on α,β-Unsaturated Aldehydes
作者:Norma Sbarbati Nudelman、Graciela V. García
DOI:10.1021/jo005698d
日期:2001.2.1
isotopic exchange reactions and trapping of two intermediates, provide clues on the several mechanistic steps of this new reaction. Extended studies revealed that beta-alkyl-substituted alpha,beta-unsaturated aldehydes and aliphatic lithium reagents did not afford good yields of the tandem reaction products, while aromatic lithium reagents gave good results. The aggregation features of the aryllithium
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.
6-aryl-2,6-hexanediones was achieved with chiral secondary amine catalyzed intramolecular aldolization. The current kinetic resolution protocol enables the synthesis of bothenantiomers of cyclohexenones with moderate to good enantioselectivity.
Efficient Addition of Allylsilanes to α,β-Enones Using Catalytic Indium and Trimethylsilyl Chloride
作者:Phil Ho Lee、Dong Seomoon、Sundae Kim、K. Nagaiah、S. V. Damle、Kooyeon Lee
DOI:10.1055/s-2003-41017
日期:——
β-Enones undergo an efficient Hosomi-Sakurai reaction with allyltrimethylsilane, in which a catalytic amount of indium is used in the presence of trimethylsilylchloride as an activator under mild conditions to produce the conjugateaddition products in good yields.