Bidentate NHC-Cobalt Catalysts for the Hydrogenation of Hindered Alkenes
作者:Zeyuan Wei、Yujie Wang、Yibiao Li、Raffaella Ferraccioli、Qiang Liu
DOI:10.1021/acs.organomet.0c00498
日期:2020.9.14
Herein, we report a series of easily accessible bidentate N-heterocyclic carbene (NHC) cobalt catalysts, which enable the hydrogenation of hindered alkenes under mild conditions. The four-coordinated bidentate NHC-Co(II) complexes were characterized by X-ray diffraction, elemental analysis, ESI-HRMS, and magnetic moment measurements, revealing a distorted-tetrahedral geometry and a high-spin configuration
Alkynes react with organoborons under a CO atmosphere in the presence of a rhodium(I) catalyst to afford mainly 5-aryl-2(5H)-furanones, α,β-unsaturated ketones, and indanones. The product selectivity can be tuned by modifying the reaction conditions.
Selective Divergent Synthesis of Indanols, Indanones, and Indenes via Acid-Mediated Cyclization of (<i>Z</i>)- and (<i>E</i>)-(2-Stilbenyl)methanols and Its Application for the Synthesis of Paucifloral F Derivatives
structurally related to the natural product paucifloral F. At higher temperatures, 1,2- and 2,3-disubstituted indenes could be selectively prepared in good to excellent yields. On the other hand, the (Z)-stilbenes, under similar conditions (PTS-Si), did not give the indanols; only the 1,2-disubstituted indenes could be obtained. To gain further insights into the stereochemistry at C2–C3 for the (Z)-stilbenes
of comparing the reaction of various aminocarbene complexes of chromium with alkynes and to ascertain several points of the mechanism of their interaction, a series of complexes derived from large cyclic amines, HN(CH2)n (n≥6) and from a small cyclic amine (n=2) was synthesized. In the case of the larger amines, all the complexes examined herein, led to the expected bridgehead lactams 12 as the major
Generation and Trapping of Cyclopropenes from 2-Alkoxy-1,1-dichlorocyclopropanes
作者:Paul Müller、Nicole Pautex
DOI:10.1002/hlca.19910740108
日期:1991.1.30
In presence of crown ether, 2-alkoxy-1,1-dichlorocyclopropanes react with t-BuOK/THF preferentially via ring opening to 2-chloroalk-2-en-1-ones and alkynones or to chlorocyclopropenes. The latter may be intercepted with 1,3-diphenylisobenzofuran, but in the absence of trapping agent, the rearrangement to vinylcarbenes does not occur.