Room-Temperature Negishi Cross-Coupling of Unactivated Alkyl Bromides with Alkyl Organozinc Reagents Utilizing a Pd/N-Heterocyclic Carbene Catalyst
摘要:
A high-yielding cross-coupling reaction of unactivated alkyl bromides possessing beta-hydrogens with alkylzinc halides utilizing a Pd/N-heterocyclic carbene (NHC) catalyst at room temperature is described. A variety of Pd sources, Pd-2(dba)(3), Pd(OAc)(2), or PdBr2, with the commercially available ligand precursor 1,3-bis(2,6-diisopropylphenyl)imidazolium chloride (IPr center dot HCl) successfully coupled 1-bromo-3-phenylpropane with n-butylzinc bromide in THF/NMP. An investigation of different NHC precursors showed that the bulky 2,6-diisopropylphenyl moiety was necessary to achieve high coupling yields (75-85%). The corresponding ethyl analogue was moderately active (11%). A range of unsymmetrical NHC precursors were prepared and evaluated. The ligand precursor containing one 2,6-diisopropylphenyl and one 2,6-diethylphenyl afforded the coupling product in 47% yield, clearly suggesting a direct relationship between the steric topography created by the flanking N-substituents and catalyst activity. Under optimal conditions, a number of alkyl bromides and alkylzinc halides possessing common functional groups (amide, nitrile, ester, acetal, and alkyne) were effectively coupled (61-92%). It is noteworthy that beta-substituted alkyl bromides and alkylzinc halides successfully underwent cross-coupling. Also, under these conditions alkyl chlorides were unaffected.
OXALIC ACID MONOAMIDE LIGAND, AND USES THEREOF IN COUPLING REACTION OF COPPER-CATALYZED ARYL HALOGEN SUBSTITUTE
申请人:Shanghai Institute of Organic Chemistry, Chinese
Academy of Sciences
公开号:EP3326715A1
公开(公告)日:2018-05-30
The present invention provides oxalic amide ligands and uses thereof in copper-catalyzed coupling reaction of aryl halides. Specifically, the present invention provides a use of a compound represented by formula I, wherein definitions of each group are described in the specification. The compound represented by formula I can be used as a ligand in copper-catalyzed coupling reaction of aryl halides for the formation of C-N, C-O and C-S bonds.
本发明提供了草酸酰胺配体及其在铜催化的芳基卤化物偶联反应中的用途。具体而言,本发明提供了一种由式 I 代表的化合物的用途,其中各基团的定义在说明书中有所描述。式 I 所代表的化合物可用作铜催化的芳基卤化物偶联反应中的配体,用于形成 C-N、C-O 和 C-S 键。
[EN] OXALIC ACID MONOAMIDE LIGAND, AND USES THEREOF IN COUPLING REACTION OF COPPER-CATALYZED ARYL HALOGEN SUBSTITUTE<br/>[FR] LIGAND DE MONOAMIDE D'ACIDE OXALIQUE, ET SES USAGES DANS UNE RÉACTION DE COUPLAGE DE SUBSTITUT HALOGÉNÉ D'ARYLE CATALYSÉ AU CUIVRE<br/>[ZH] 草酸酰胺类配体及其在铜催化芳基卤代物偶联反应中的用途