Copper-catalyzed enantioselective 1,2-borylation of 1,3-dienes
作者:Yangbin Liu、Daniele Fiorito、Clément Mazet
DOI:10.1039/c8sc01538d
日期:——
borylation of 2-substituted 1,3-dienes is reported. The use of a chiral phosphanamine ligand is essential in achieving high chemo-, regio-, diastereo- and enantioselectivity. It provides access to a variety of homoallylic boronates in consistently high yield and enantiomeric excess with 2-aryl and 2-heteroaryl 1,3-dienes as well as sterically demanding 2-alkyl 1,3-dienes. Preliminary investigations
nickel(II) precatalysts for the preparation of 2-substituted 1,3-dienes by a Kumada cross-coupling between vinyl magnesium bromide and vinyl phosphates is described. This is noteworthy as engaging only one vinyl derivative in a transition-metal-catalyzed cross-coupling reaction is already reputedly challenging. Salient features of this method are its operational simplicity, the mild reaction conditions, the
Chiral β-iodoamines by urea-catalysed iodocyclization of trichloroacetimidates
作者:Cheyenne S. Brindle、Charles S. Yeung、Eric N. Jacobsen
DOI:10.1039/c3sc50410g
日期:——
Highly enantioselective vicinal iodoamination of olefins is accomplished through the iodocyclization of alkenyl trichloroacetimidates catalysed by a new chiral Schiff-base urea derivative. The resulting products are converted readily to a variety of polyfunctional amine-containing chiral building blocks.
Magnesium hydride, generated in situ by solvothermal treatment of sodium hydride and magnesium iodide in tetrahydrofuran, was found capable of inducing regio and stereocontrolled hydromagnesiation of 2-aryl-1,3-dienes to form allylmagnesium species. Downstream functionalization of the resulting allylmagnesium species with various electrophiles provided synthetically valuable synthons such as homoallylic
Synthesis of Nitrile Bearing Acyclic Quaternary Centers through Co(III)‐Catalyzed Sequential C−H Bond Addition to Dienes and
<i>N</i>
‐Cyanosuccinimide
作者:Sun Dongbang、Jonathan A. Ellman
DOI:10.1002/anie.202010735
日期:2021.1.25
quaternary centers bearing nitriles by cobalt‐catalyzed C−H bond activation and sequential addition to internally substituted 1,3‐dienes and an electrophilic cyanating reagent with high regio and stereocontrol. 2‐Aryl and alkyl monosubstituted dienes provide α‐aryl and α‐alkyl α‐methyl‐substituted nitriles, respectively. An even wider variety of functionality can be installed at the quaternary carbon by