Kidonakis Marios, Stratakis Manolis
Department of Chemistry, University of Crete, 71003 Voutes, Heraklion, Greece.
Nanomaterials (Basel). 2021 Jan 18;11(1):248. doi: 10.3390/nano11010248.
Supported Au nanoparticles on TiO (1 mol%) are capable of catalyzing the reduction of the carbene-like diazo functionality of α-diazocarbonyl compounds into a methylene group [C=(N) → CH] by NHBH or NaBH in methanol as solvent. The Au-catalyzed reduction that occurs within a few minutes at room temperature formally requires one hydride equivalent (B-H) and one proton that originates from the protic solvent. This pathway is in contrast to the Pt/CeO-catalyzed reaction of α-diazocarbonyl compounds with NHBH in methanol, which leads to the corresponding hydrazones instead. Under our stoichiometric Au-catalyzed reaction conditions, the ketone-type carbonyls remain intact, which is in contrast to the uncatalyzed conditions where they are selectively reduced by the boron hydride reagent. It is proposed that the transformation occurs via the formation of chemisorbed carbenes on Au nanoparticles, having proximally activated the boron hydride reagent. This protocol is the first general example of catalytic transfer hydrogenation of the carbene-like α -ketodiazo functionality.
负载在TiO（1摩尔%）上的金纳米颗粒能够在甲醇作为溶剂的条件下，通过NHBH或NaBH将α-重氮羰基化合物的类卡宾重氮官能团催化还原为亚甲基[C=(N) → CH]。在室温下几分钟内发生的金催化还原反应，理论上需要一当量的氢化物（B-H）和一个来自质子性溶剂的质子。该反应途径与甲醇中α-重氮羰基化合物与NHBH的Pt/CeO催化反应形成对比，后者会生成相应的腙。在我们的化学计量金催化反应条件下，酮型羰基保持完整，这与未催化条件下它们被硼氢化试剂选择性还原的情况相反。有人提出，该转化过程是通过在金纳米颗粒上形成化学吸附的卡宾来实现的，在此过程中硼氢化试剂被近端活化。该方法是类卡宾α-酮重氮官能团催化转移氢化的首个通用实例。
