Reactions of vinylsilanes with lewis acid-activated iodosylbenzene: stereospecific syntheses of vinyliodonium tetrafluoroborates and their reactions as highly activated vinyl halides
salts behave like the highly activated species of vinyl iodides due to the high leaving ability of the iodine(III) substituents. Thus, a variety of substituted olefins including α-cyano and α-nitro olefins, vinyl sulfides, vinyl halides, and α,β-unsaturated esters, were synthesized from under mild conditions. A ligand coupling mechanism via the formation of 10-I-3 intermediate containing a copper(III)
Development of Regio- and Face-selective [2 + 3] Cycloaddition Reactions of Readily Preparable Oxime-substituted Nitrile Oxides with Silicon-linked Allylic-alcohol Moieties for Intramolecular Reactions
作者:Nao Umemoto、Ayumi Imayoshi、Kazunori Tsubaki
DOI:10.1246/cl.220258
日期:2022.9.5
typically prepared in situ from nitroalkanes and converted to 2-isoxazoline heterocycles upon [2 + 3] cycloaddition with alkenes, providing synthetically useful intermediates such as β-hydroxy ketones and γ-amino alcohols. Herein, we prepared oxime-substituted nitrile oxides bound to allylic-alcohol derivatives through a silicon atom and demonstrated their intramolecular cycloaddition reactions. The desired
unique diamidine ligand catalyzes asymmetric NaBH4 reduction of C3‐disubstituted (E)‐ and (Z)‐2‐propenoates, including C3‐oxygen‐ and nitrogen‐substituted substrates with high enantioselectivity. Analysis by X‐ray diffraction, 1H NMR spectroscopy, ring‐opening radical‐clock and D‐labeling reactions, and the structure/selectivity relationship suggest that a mechanism of CoH‐involved non‐single‐electron transfer
独特的二am基配体的新Co络合物催化NaBH 4还原不对称还原C3-二取代的(E)和(Z)-2-丙烯酸酯,包括具有高对映选择性的C3-氧和氮取代的底物。X射线衍射,1 H NMR光谱,开环自由基钟和D标记反应以及结构/选择性关系的分析表明,CoH参与的非单电子转移1,4加成的机理有所不同C2对映体。新型CoH 2(BH 3)2配合物的定量分离已支持了CoH物种的参与。