Phosphine-Free Manganese Catalyst Enables Selective Transfer Hydrogenation of Nitriles to Primary and Secondary Amines Using Ammonia–Borane
作者:Koushik Sarkar、Kuhali Das、Abhishek Kundu、Debashis Adhikari、Biplab Maji
DOI:10.1021/acscatal.0c05406
日期:2021.3.5
primary and secondary amines by nitrilehydrogenation, employing a borrowing hydrogenation strategy. A class of phosphine-free manganese(I) complexes bearing sulfur side arms catalyzed the reaction under mild reaction conditions, where ammonia–borane is used as the source of hydrogen. The synthetic protocol is chemodivergent, as the final product is either primary or secondary amine, which can be controlled
2D sp
<sup>2</sup>
Carbon‐Conjugated Porphyrin Covalent Organic Framework for Cooperative Photocatalysis with TEMPO
作者:Ji‐Long Shi、Rufan Chen、Huimin Hao、Cheng Wang、Xianjun Lang
DOI:10.1002/anie.202000723
日期:2020.6.2
2D covalentorganicframeworks (COFs) are receiving ongoing attention in semiconductor photocatalysis. Herein, we present a photocatalytic selective chemical transformation by combining sp2 carbon-conjugated porphyrin-based covalentorganicframework (Por-sp2 c-COF) photocatalysis with TEMPO catalysis illuminated by 623 nm red light-emitting diodes (LEDs). Highly selective conversion of amines into
two new C(sp3)−C(sp2) bonds using a bench-stable Ni/bipyridine/Zn system featuring a broad substrate scope and excellent diastereoselectivity, which provides an effective platform for the remote aryl group migration and arylation of amino acid esters via redox-neutral C(sp3)−C(sp2) bond cleavage. Mechanistically, this cascade reaction is accomplished by combining two powerful catalyticcycles consisting
Lend me your hydrogen! The first transition‐metal‐catalyzed alkylations of indoles with aliphatic amines proceeding under transfer hydrogenation conditions are developed (see scheme). This reaction is based on the borrowing hydrogen methodology.
An enantioselective ring‐closing C(sp3)−Hamination of 2‐azidoacetamides is catalyzed by a chiral‐at‐metal ruthenium complex and provides chiral imidazolidin‐4‐ones in 31–95 % yield, with enantioselectivities of up to 95 % ee, and at catalyst loadings down to 0.1 mol % (turnover number (TON)=740). To our knowledge, this is the first example of a highly enantioselectiveC(sp3)−Hamination with aliphatic