A silica‐supportedtripodtriarylphosphane (Silica‐3p‐TPP), containing a triphenylphosphane‐type core tripodally immobilized on the silica surface, allows rhodium‐ and iridium‐catalyzedC(sp3)Hborylations of amide, urea and alkylpyridine derivatives. The 31P CP/MAS NMR studies for the coordination behavior of the tripod phosphane towards a rhodium complex indicate efficient site isolation of the
的二氧化硅负载的三脚架triarylphoSPhane(二氧化硅-3P-TPP),含tripodally固定在二氧化硅表面上的三苯基膦型铁芯,使得铑和铱催化的C(SP 3) ħ酰胺,脲和烷基吡啶衍生物的borylations。对三脚架膦对铑配合物的配位行为的31 P CP / MAS NMR研究表明,每个膦烷中心都有效地被隔离,从而允许与金属中心进行独立的单P配位。
Threefold Cross-Linked Polystyrene-Triphenylphosphane Hybrids: Mono-P-Ligating Behavior and Catalytic Applications for Aryl Chloride Cross-Coupling and C(sp<sup>3</sup>)H Borylation
the presence of a tris(p‐vinylphenyl)phosphane cross‐linker. These hybrids favor mono‐P‐ligation to transition‐metal complexes and are useful for challenging catalysis, such as Pd‐catalyzedCC/CN couplings with unactivated chloroarenes and Ir‐ or Rh‐catalyzedC(sp3)Hborylations.
共价键合的聚苯乙烯-膦杂化物是通过在三(对-乙烯基苯基)膦交联剂存在下苯乙烯自由基乳液聚合的方法制备的。这些杂种利于单-P-结扎到过渡金属配合物,并且可用于具有挑战性的催化,如Pd催化的C ^ C / C N型联轴器与未活化的氯代芳烃和IR-或Rh催化的C(SP 3) ħ硼化。
Amide directed iridium C(sp3)–H borylation catalysis with high N-methyl selectivity
作者:Jonathan E. Dannatt、Anshu Yadav、Milton R. Smith、Robert E. Maleczka
DOI:10.1016/j.tet.2021.132578
日期:2022.3
monoanionic ligand system was developed to enable iridiumcatalyzedC(sp3)–H activation borylation of N-methyl amides. Borylated amides were obtained in moderate to good isolated yields, and exclusive mono-borylation allowed the amide to be the limiting reagent. Selectivity for C(sp3)–H activation was demonstrated in the presence of sterically available C(sp3)–H bonds. Competitive kinetic isotope studies
α-Amidoboronate esters by amide-directed alkane C H borylation
作者:Stephen N. Hyland、Ellie A. Meck、Mariola Tortosa、Timothy B. Clark
DOI:10.1016/j.tetlet.2019.03.020
日期:2019.4
alpha-Amidoboronic acids have received significant attention in recent years following the development of Bortezomib as an FDA-approved treatment of multiple myeloma and mantle cell lymphoma. More versatile methods to access alpha-amidoboronic acids continue to be developed. A direct method to access the precursors, alpha-amidoboronate esters, by iridium-catalyzed C-H borylation of amides was developed using a readily available ligand/catalyst combination. Although the scope is limited, good yields of alpha-amidoboronate esters are achieved in high selectivity. Conversion of the boronate esters to the corresponding alpha-amidoboronic acids was also demonstrated. (C) 2019 Elsevier Ltd. All rights reserved.