Manganese-catalyzed homogeneous hydrogenation of ketones and conjugate reduction of α,β-unsaturated carboxylic acid derivatives: A chemoselective, robust, and phosphine-free in situ-protocol
作者:Thomas Vielhaber、Christoph Topf
DOI:10.1016/j.apcata.2021.118280
日期:2021.8
glove-box-free catalytic protocol for the manganese-catalyzed hydrogenation of ketones and conjugated CCbonds of esters and nitriles. The respective catalyst is readily assembled in situ from the privileged [Mn(CO)5Br] precursor and cheap 2-picolylamine. The catalytic transformations were performed in the presence of t-BuOK whereby the corresponding hydrogenation products were obtained in good to excellent yields
我们传达了一种用户友好且无需手套箱的催化协议,用于酮和酯和腈的共轭 C C键的锰催化氢化。相应的催化剂很容易由特权 [Mn(CO) 5 Br] 前体和廉价的 2-吡啶甲胺原位组装。催化转化在t- BuOK存在下进行,从而以良好至极好的收率获得相应的氢化产物。所描述的系统提供了对仲醇和饱和酯的快速和原子效率的访问,避免了使用氧敏感和昂贵的基于膦的配体。
Chemistry and folding of photomodulable peptides – stilbene and thioaurone-type candidates for conformational switches
作者:Máté Erdélyi、Miranda Varedian、Christian Sköld、Ida B. Niklasson、Johanna Nurbo、Åsa Persson、Jonas Bergquist、Adolf Gogoll
DOI:10.1039/b812001c
日期:——
Optimized synthetic strategies for the preparation of photoswitchable molecular scaffolds based on stilbene or on thioaurone chromophores and their conformationally directing properties, as studied by computations and by NMR spectroscopy, are addressed. For the stilbene peptidomimetics 1, 2 and 3, the length of connecting linkers between the chromophore and the peptide strands was varied, resulting in photochromic dipeptidomimetics with various flexibility. Building blocks of higher rigidity, based on para-substituted thioaurone (4 and 6) and meta-substituted thioaurone chromophores (5 and 7) are shown to have a stronger conformationally directing effect. Design, synthesis, theoretical and experimental conformational analyses are presented.
β-Ketophosphonates formation via deesterification or deamidation of cinnamyl/alkynyl carboxylates or amides with H-phosphonates
作者:Yao Zhou、Mingxin Zhou、Ming Chen、Jihu Su、Jiangfeng Du、Qiuling Song
DOI:10.1039/c5ra23950h
日期:——
We report here an unprecedented Fe/Cu synergistically catalyzed deesterificative or deamidative oxyphosphorylation of unsaturated carboxylates or amides with H-phosphonates.
Cross-Linked Thiazolidine Network as Support for Palladium: A New Catalyst for Suzuki and Heck Reactions
作者:Lucia Anna Bivona、Francesco Giacalone、Luigi Vaccaro、Carmela Aprile、Michelangelo Gruttadauria
DOI:10.1002/cctc.201500408
日期:2015.8.17
sodium borohydride afforded a thiazolidine‐based material that acted as ligands for the Pd species. The thiazolidine‐based palladiumcatalyst was fully characterized and, working in only 0.1 mol % amount, displayed good activity in the Suzuki–Miyaura and in the Heckreactions. Several biphenyl and alkene compounds could be prepared in high yields. The catalytic material proved to be fully recoverable and
A Photocatalytic Regioselective Direct Hydroaminoalkylation of Aryl-Substituted Alkenes with Amines
作者:Natalia A. Larionova、Jun Miyatake Ondozabal、Emily G. Smith、Xacobe C. Cambeiro
DOI:10.1021/acs.orglett.1c01715
日期:2021.7.16
hydroaminoalkylation of cinnamate esters has been developed. The reaction involves the regioselective addition of α-aminoalkyl radicals generated from aniline derivatives or aliphatic amines to the α-position of unsaturated esters. The scope of aromatic alkenes was extended to styrenes undergoing hydroaminoalkylation with anti-Markovnikov selectivity, which confirms the importance of the aromatic group