The comprehensive study of the reactions of carbonylcompounds and ethyl diazoacetate in the presence of a Brønsted acid catalyst is described. In result, a broad range of 3-oxo-esters were synthesized from a variety of ketones and aliphatic aldehydes by 1,2-aryl/alkyl/hydride shift. Aryl–methyl ketones produced only aryl-migrated products, whereas other ketones yielded a mixture of products. For diaryl
Environmentally benign nucleophilic substitution reaction of arylalkyl halides in water using CTAB as the inverse phase transfer catalyst
作者:Atul K. Godha、Jayaraman Thiruvengadam、Viswanadhan Abhilash、Prajwal Balgi、A. V. Narayanareddy、Kumaresan Vignesh、Amol V. Gadakh、A. M. Sathiyanarayanan、Sambasivam Ganesh
DOI:10.1039/c9nj03941d
日期:——
An environmentally benign, practically scalable and highly selective C-arylalkylation of active methylene compounds is developed using CTAB as the inverse phase transfer catalyst in water. The methodology developed is elaborated into the one-pot synthesis of quinoline derivatives and also applicable to the regioselective N-aralkyl of 2-pyridones.
Suzuki-Miyaura cross-coupling of 3,4-disubstituted 5-bromoisoxazoles: An efficient access to trisubstituted isoxazoles
作者:Masato Tsuda、Taiki Morita、Hiroyuki Nakamura
DOI:10.1016/j.tetlet.2021.153185
日期:2021.7
The Suzuki-Miyaura cross-coupling of 3,4-disubstituted 5-bromoisoxazoles 1 at the C5 position has successfully proceeded in the presence of Pd2(dba)3 and P(t-Bu)3·HBF4 catalysts to give the corresponding trisubstituted isoxazoles 3 in good to high yields while suppressing the formation of ketone 4 as a byproduct. The use of bulky phosphine ligand P(t-Bu)3·HBF4 is essential for the current transformation
6‐bis(oxazoline) (pybox) ligands for asymmetric transition metal catalysis is introduced by adding a bidentate ligand to modulate the electronic properties and asymmetric induction. Specifically, a ruthenium(II) pybox fragment is combined with a cyclometalated N‐heterocyclic carbene (NHC) ligand to generate catalysts for enantioselective transition metal nitrenoid chemistry, including ring contraction
通过添加双齿配体来调节电子性质和不对称诱导,提出了扩大手性吡啶-2,6-双(恶唑啉)(pybox)配体在不对称过渡金属催化中的应用的策略。具体来说,钌 (II) pybox 片段与环金属化 N-杂环卡宾 (NHC) 配体结合,生成用于对映选择性过渡金属氮烯化学的催化剂,包括环收缩为手性 2H-氮丙啶(2000 TON 时高达 97% ee)和对映选择性 C(sp 3 )−H 胺化(50 TON 时高达 97 % ee)。
Regioselective Catalytic Asymmetric C-Alkylation of Isoxazolinones by a Base-Free Palladacycle-Catalyzed Direct 1,4-Addition
作者:Tina Hellmuth、Wolfgang Frey、René Peters
DOI:10.1002/anie.201410933
日期:2015.2.23
asymmetric alkylations of isoxazolinones forming all‐C‐substituted quaternary stereocenters. The present studies were driven by the question of how to control the regioselectivity in the competition of different nucleophilic positions. The investigation of a direct 1,4‐addition uncovered that a sterically demanding palladacycle catalyst directs the reactivity in the absence of a base nearly exclusively to