Selective and Serial Suzuki–Miyaura Reactions of Polychlorinated Aromatics with Alkyl Pinacol Boronic Esters
نویسندگان
چکیده
Among cross-coupling reactions, the Suzuki-Miyaura transformation stands out because of its practical advantages, including the commercial availability and low toxicity of the required reagents, mild reaction conditions, and functional group compatibility. Nevertheless, few conditions can be used to cross-couple alkyl boronic acids or esters with aryl halides, especially 2-pyridyl halides. Herein, we describe two novel Suzuki-Miyaura protocols that enable selective conversion of polychlorinated aromatics, with a focus on reactions to convert 2,6-dichloropyridines to 2-chloro-6-alkylpyridines or 2-aryl-6-alkylpyridines.
منابع مشابه
Convenient methods for preparing π-conjugated linkers as building blocks for modular chemistry
Simple, straightforward and optimized procedures for preparing extended pi-conjugated linkers are described. Either unsubstituted or 4-donor substituted pi-linkers bearing a styryl, biphenyl, phenylethenylphenyl, and phenylethynylphenyl pi-conjugated backbone are functionalized with boronic pinacol esters as well as with terminal acetylene moieties allowing their further use as building blocks ...
متن کاملNickel-Catalyzed Double Bond Transposition of Alkenyl Boronates for in Situ syn-Selective Allylboration Reactions.
The transposition of a homoallyl pinacol boronic ester was realized by a highly reactive nickel-catalyst system comprising NiCl2(dppp), zinc powder, ZnI2, and Ph2PH. The in situ generated Z-crotyl pinacol boronic esters were reacted with various aldehydes to form syn-homoallylic alcohols in high diastereoselectivities. The present nickel-catalyzed reaction is complementary to the iridium-cataly...
متن کاملSynthetic method for multifunctionalized oligoarenes using pinacol esters of hydroxyphenylboronic acids.
A synthetic method for multifunctionalized oligoarenes using rapid Suzuki-Miyaura coupling of pinacol esters of hydroxyphenylboronic acids and subsequent triflation of the hydroxy group was developed.
متن کاملObservations on the deprotection of pinanediol and pinacol boronate esters via fluorinated intermediates.
Methods for the deprotection of pinanediol and pinacol esters of various boronic acids via fluoroborane intermediates were evaluated. Treatment of the boronate esters with potassium hydrogen difluoride normally gives trifluoroborate salts; in the case of alpha-amido alkyl or o-amido phenyl boronate esters, aqueous workup gives difluoroboranes. Procedures for transformation of both trifluorobora...
متن کاملStereospecific conversion of alcohols into pinacol boronic esters using lithiation-borylation methodology with pinacolborane.
The synthesis of primary and secondary pinacol boronic esters via lithiation-borylation of carbamates and benzoates with pinacolborane is described. This new protocol enables the highly selective synthesis of enantioenriched and geometrically defined boronic esters that cannot otherwise be accessed by alternative methodologies.
متن کامل