Pd/C[Ph2S], was developed to achieve the highly chemoselectivehydrogenation of alkenes, acetylenes, azides, and nitrogroups in the presence of aromatic ketones, halides, benzyl esters, and N-Cbz protective groups. Instrumental analyses of the heterogeneous catalyst demonstrated that diphenyl sulfide was embedded on Pd/C via coordination of its sulfur atom to palladium metal or physical interaction with graphite
开发了一种固定在钯碳体系上的二苯硫醚Pd / C [Ph 2 S],以在芳族酮,卤化物,苄基酯存在下实现烯烃,乙炔,叠氮化物和硝基的高化学选择性氢化。和N-Cbz保护基。对非均相催化剂的仪器分析表明,二苯硫醚通过其硫原子与钯金属的配位或与活性炭石墨层的物理相互作用而嵌入Pd / C中。催化剂可被回收并重复使用至少五次,而反应活性没有任何显着损失。
Highly chemoselective reduction of azides to amines by Fe(0) nanoparticles in water at room temperature
作者:Subir Panja、Debasish kundu、Sabir Ahammed、Brindaban C. Ranu
DOI:10.1016/j.tetlet.2017.07.076
日期:2017.8
A highly chemoselective reduction of aryl, heteroaryl, acyl and sulfonylazides to the corresponding amines has been achieved by Fe(0) nanoparticles in water at roomtemperature in the absence of external hydride source. Several readily reducible functionalities including alkene, alkyne, S-S linkage, OTBDMS remain unaffected during reduction.
the basis of sequential azide–aryne and azide–alkyne cycloadditions. The key to success was efficient halogen–metalexchange reaction-mediated generation of aryne from ortho-iodoaryl triflates bearing a base-sensitive terminal alkyne moiety, which was achieved using trimethylsilylmethyl Grignardreagent.
hydrogenation catalyzed heterogeneously by palladium on boronnitride (Pd/BN) in methanol realized the chemoselective hydrogenation of only azides, alkenes, and alkynes in the presence of other reducible functionalities such as benzyl ethers, aryl halides, aryl ketones, and nitro groups. Furthermore, the totally chemoselective semihydrogenation of alkynes could also be achieved without the reduction
Chemoselective Homologation–Deoxygenation Strategy Enabling the Direct Conversion of Carbonyls into (<i>n+1</i>)-Halomethyl-Alkanes
作者:Margherita Miele、Andrea Citarella、Thierry Langer、Ernst Urban、Martin Zehl、Wolfgang Holzer、Laura Ielo、Vittorio Pace
DOI:10.1021/acs.orglett.0c02831
日期:2020.10.2
The sequential installation of a carbenoid and a hydride into a carbonyl, furnishing halomethyl alkyl derivatives, is reported. Despite the employment of carbenoids as nucleophiles in reactions with carbon-centered electrophiles, sp3-type alkyl halides remain elusive materials for selective one-carbon homologations. Our tactic levers on using carbonyls as starting materials and enables uniformly high