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Semihydrogenation of alkynes to alkenes is an important and fundamental reaction in many industrial and synthetic applications and often suffers low selectivity because of the overhydrogenation. Here, highly selective semihydrogenation of alkynes is achieved by using H2 ex situ generated from formic acid dehydrogenation with palladium (Pd)-based bimetallic catalysts through a two-chamber reactor in this work, realizing efficient utilization of H2 and selective production of alkenes under mild reaction conditions. The Pd-based bimetallic catalysts show excellent catalytic performances for semihydrogenation of alkynes (PdZn bimetallic catalyst) and dehydrogenation of formic acid (PdAg bimetallic catalyst) in the two-chamber reactor. 相似文献
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Selective hydrogenation of nitriles and alkynes is crucial considering the vast applications of reduced products in industries and in the synthesis of bioactive compounds. Particularly, the late 3d transition metal catalysts (manganese, iron, cobalt, nickel and copper) have shown promising activity for the hydrogenation of nitriles to primary amines, secondary amines and imines. Similarly, semihydrogenation of alkynes to E‐ and Z‐alkenes by 3d metals is adequately successful both via the transfer hydrogenation and by using molecular hydrogen. The emergence of 3d transition metals in the selective synthesis of industrially relevant amines, imines and alkenes makes this protocol more attractive. Herein, we provide a concise overview on the late 3d transition metal‐catalyzed hydrogenation of nitriles to amines and imines as well as semihydrogenation of alkynes to alkenes. 相似文献
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Dr. Matthew P. Conley Ruben M. Drost Dr. Mathieu Baffert Dr. David Gajan Prof. Dr. Cornelis Elsevier Dr. W. Trent Franks Prof. Dr. Hartmut Oschkinat Laurent Veyre Alexandre Zagdoun Dr. Aaron Rossini Dr. Moreno Lelli Dr. Anne Lesage Dr. Gilles Casano Dr. Olivier Ouari Prof. Dr. Paul Tordo Prof. Dr. Lyndon Emsley Prof. Dr. Christophe Copéret Dr. Chloé Thieuleux 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(37):12234-12238
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Pd–Pb Alloy Nanocrystals with Tailored Composition for Semihydrogenation: Taking Advantage of Catalyst Poisoning 下载免费PDF全文
Dr. Wenxin Niu Dr. Yongjun Gao Dr. Weiqing Zhang Prof. Ning Yan Prof. Xianmao Lu 《Angewandte Chemie (International ed. in English)》2015,54(28):8271-8274
Metallic nanocrystals (NCs) with well‐defined sizes and shapes represent a new family of model systems for establishing structure–function relationships in heterogeneous catalysis. Here in this study, we show that catalyst poisoning can be utilized as an efficient strategy for nanocrystals shape and composition control, as well as a way to tune the catalytic activity of catalysts. Lead species, a well‐known poison for noble‐metal catalysts, was investigated in the growth of Pd NCs. We discovered that Pb atoms can be incorporated into the lattice of Pd NCs and form Pd–Pb alloy NCs with tunable composition and crystal facets. As model catalysts, the alloy NCs with different compositions showed different selectivity in the semihydrogenation of phenylacetylene. Pd–Pb alloy NCs with better selectivity than that of the commercial Lindlar catalyst were discovered. This study exemplified that the poisoning effect in catalysis can be explored as efficient shape‐directing reagents in NC growth, and more importantly, as a strategy to tailor the performance of catalysts with high selectivity. 相似文献
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Yongmeng Wu Dr. Cuibo Liu Dr. Changhong Wang Dr. Siyu Lu Prof. Bin Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(47):21356-21361
We reported a selective semihydrogenation (deuteration) of numerous terminal and internal alkynes using H2O (D2O) as the H (D) source over a Pd-P alloy cathode at a lower potential. P-doping caused the enhanced specific adsorption of alkynes and the promoted intrinsic activity for producing adsorbed atomic hydrogen (H*ads) from water electrolysis. The semihydrogenation of alkynes could be accomplished at a lower potential with up to 99 % selectivity and 78 % Faraday efficiency of alkene products, outperforming pure Pd and commercial Pd/C. This electrochemical semihydrogenation of alkynes might proceed via a H*ads addition pathway rather than a proton-coupled electron transfer process. The decreased amount of H*ads at a lower potential and the more preferential adsorption of the Pd-P to C≡C π bond than C=C moiety resulted in the excellent alkene selectivity. This method was capable of producing mono-, di-, and tri-deuterated alkenes with up to 99 % deuterium incorporation. 相似文献
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Julián Bergueiro Dr. Javier Montenegro Prof. Dr. Carlos Saá Prof. Dr. Susana López 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(44):14100-14107
An expeditious, highly efficient approach to 11‐cis‐retinoids was achieved by semihydrogenation of a readily available 11‐yne precursor through a hydrosilylation–protodesilylation protocol. The complete chemo‐, regio‐, and syn‐stereoselectivity of the method also allowed direct access to 11‐ and 12‐monodeutero‐, and 11,12‐dideutero‐11‐cis‐retinoids. The analogous trans series was not accessible by this route, and was synthesized by means of Hiyama coupling. 相似文献
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A Palladium Nanoparticle–Nanomicelle Combination for the Stereoselective Semihydrogenation of Alkynes in Water at Room Temperature 下载免费PDF全文
Eric D. Slack Christopher M. Gabriel Prof. Dr. Bruce H. Lipshutz 《Angewandte Chemie (International ed. in English)》2014,53(51):14051-14054
The addition of NaBH4 to Pd(OAc)2 in water containing nanomicelles leads to the generation of H2 and Pd nanoparticles. Subsequent reduction of disubstituted alkynes affords Z‐alkenes in high yields. These reactions are general, take place in water at ambient temperatures, and offer recycling of the aqueous reaction mixture along with low overall E Factors. 相似文献