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
A Nickel Catalyst for the Addition of Organoboronate Esters to Ketones and Aldehydes
作者:Jean Bouffard、Kenichiro Itami
DOI:10.1021/ol9017613
日期:2009.10.1
Ni(cod)2/IPr catalyst promotes the intermolecular 1,2-addition of arylboronate esters to unactivated aldehydes and ketones. Diaryl, alkyl aryl, and dialkyl ketones show good reactivity under mild reaction conditions (≤80 °C, nonpolar solvents, no strong base or acid additives). A dramatic ligand effect favors either carbonyl addition (IPr) or C−OR cross-coupling (PCy3) with aryl ether substrates. A Ni(0)/Ni(II)
An efficient and highly regio- and stereoselctive Pd-catalyzed β-arylation method for the formation of β-aryl allylicalcohols, employing aryl iodides, 1-bromo-2-iodobenzenes, and 2-bromobezaldehydes as coupling partners, is presented. The β-aryl allylicalcohols formed in this Pd-catalyzed transformation is unexpected under conventional Jeffery conditions without the assistance of silver salt. It
synthesis of N-cyanomethyl amides from allylic alcohols with AIBN as the nitrile source is developed. Owing to the coordination effect with the copper catalyst, a ketenimine intermediate is formed via couplings of isobutyronitrile radicals. The copper-activated ketenimine could subsequently be intercepted by allylic alcohols and undergo Claisen rearrangement to furnish N-cyanomethyl amides. Further