<i>N</i>-Methoxy-<i>N</i>-methylcyanoformamide, a Highly Reactive Reagent for the Formation of β-Keto Weinreb Amides and Unsymmetrical Ketones
作者:Jeremy Nugent、Brett D. Schwartz
DOI:10.1021/acs.orglett.6b01844
日期:2016.8.5
N-methoxy-N-methylcarbamoylimidazole, is reported. This reagent enables the one-pot preparation of β-carbonyl Weinreb amides from lithium enolates, one-carbon homologated Weinreb amides, and unsymmetrical ketones in one-pot procedures from various organometallic species.
Sc(OTf)<sub>3</sub>-Catalyzed Iodocyclization/Ritter-Type Amidation of <i>N</i>-Alkoxypropiolamides: A Synthetic Strategy for Isoxazol-3(2<i>H</i>)-ones
A Sc(OTf)3-catalyzed iodocyclization/Ritter-type amidation of N-alkoxypropiolamides for the synthesis of 4-iodoisoxazol-3(2H)-ones bearing an amide group has been developed. This domino protocol allows the construction of a valuable heterocycle, isoxazol-3(2H)-one, as well as the introduction of two functional groups. The reaction has a broad substrate scope and can be carried out on a large scale
已经开发了一种 Sc(OTf) 3催化的N-烷氧基丙酰胺的碘环化/Ritter 型酰胺化,用于合成带有酰胺基团的 4-iodoisoxazol-3(2 H )-ones。这种多米诺骨牌协议允许构建有价值的杂环异恶唑-3(2 H )-one,以及引入两个官能团。该反应底物范围广,可大规模进行。对照实验表明,Sc(OTf) 3作为碘环化和酰胺化步骤的双重活化剂。此外,底物中的N-烷氧基抑制了一些副反应。
Enantioselective Addition of Alkynyl Ketones to Nitroolefins Assisted by Brønsted Base/H‐Bonding Catalysis
作者:Teresa E. Campano、Igor Iriarte、Olatz Olaizola、Julen Etxabe、Antonia Mielgo、Iñaki Ganboa、José M. Odriozola、Jesús M. García、Mikel Oiarbide、Claudio Palomo
DOI:10.1002/chem.201805542
日期:2019.3.21
sets of enolizable alkynyl ketones (including methyl ynones with α‐aryl, α‐alkenyl, and α‐alkoxy groups) were able to react smoothly with nitroolefins with the assistance of bifunctional Brønsted base/H‐bond catalysts to provide adducts with two consecutive tertiary stereocenters in a highly diastereo‐ and enantioselective fashion. Further transformation of the obtained adducts into optically active acyclic
The first regio-, diastereo-, and enantioselective direct Michaelreaction of β,γ-unsaturated ketones with nitroolefins is enabled by Brønsted base/hydrogen-bonding bifunctional catalysis. A squaramide-substituted tertiary amine catalyzes the reaction of a broad range of β,γ-unsaturated ketones to proceed at the α-site exclusively, giving rise to adducts with two consecutive tertiary carbon stereocenters
Gold-Catalyzed Hydrofluorination of Electron-Deficient Alkynes: Stereoselective Synthesis of β-Fluoro Michael Acceptors
作者:Thomas J. O’Connor、F. Dean Toste
DOI:10.1021/acscatal.8b01341
日期:2018.7.6
The gold(I)-catalyzed, stereoselective hydrofluorination of electron-deficient alkynes with triethylamine trihydrogen fluoride (Et3N·3HF) is described. Fluorinated α,β-unsaturated aldehydes, amides, esters, ketones, and nitriles were isolated in moderate to good yields as single diastereomers. In all but four cases, the (Z)-vinyl fluorides were initially formed in ≥97% diastereoselectivity. This work