628691-74-7Relevant academic research and scientific papers
Ti(O iPr)4-Enabled Dual Photoredox and Nickel-Catalyzed Arylation and Alkenylation of Cyclopropanols
Varabyeva, Nastassia,Barysevich, Maryia,Aniskevich, Yauhen,Hurski, Alaksiej
, p. 5452 - 5456 (2021/07/21)
Readily available from esters or ketones, cyclopropanols are inclined to undergo diverse ring-opening transformations. Their one-electron oxidation is a conventional way to β-carbonyl radicals. However, despite this fact, their application as a coupling partner in dual photoredox and nickel-catalyzed reactions with organic halides remains underdeveloped. Here, we report that the Ti(OiPr)4 additive enables this elusive cross-coupling with aryl and alkenyl bromides leading to β-substituted ketones.
Late-Stage Intermolecular Allylic C-H Amination
Clark, Joseph R.,Dixon, Charlie F.,Feng, Kaibo,Han, Wei,Ide, Takafumi,Koch, Vanessa,Teng, Dawei,Wendell, Chloe I.,White, M. Christina
, p. 14969 - 14975 (2021/10/01)
Allylic amination enables late-stage functionalization of natural products where allylic C-H bonds are abundant and introduction of nitrogen may alter biological profiles. Despite advances, intermolecular allylic amination remains a challenging problem due to reactivity and selectivity issues that often mandate excess substrate, furnish product mixtures, and render important classes of olefins (for example, functionalized cyclic) not viable substrates. Here we report that a sustainable manganese perchlorophthalocyanine catalyst, [MnIII(ClPc)], achieves selective, preparative intermolecular allylic C-H amination of 32 cyclic and linear compounds, including ones housing basic amines and competing sites for allylic, ethereal, and benzylic amination. Mechanistic studies support that the high selectivity of [MnIII(ClPc)] may be attributed to its electrophilic, bulky nature and stepwise amination mechanism. Late-stage amination is demonstrated on five distinct classes of natural products, generally with >20:1 site-, regio-, and diastereoselectivity.
Stereoselection in Intramolecular Diels-Alder Reactions of 2-Cyano-1-azadienes: Indolizidine and Quinolizidine Synthesis
Tay, Gidget C.,Sizemore, Nicholas,Rychnovsky, Scott D.
, p. 3050 - 3053 (2016/07/13)
Progress toward understanding the scope and diastereoselectivity of intramolecular Diels-Alder reactions using 2-cyano-1-azadienes is described herein. The resulting cyanoenamine products are underutilized intermediates in organic synthesis. Assembly of the Diels-Alder precursors was achieved using an improved imine condensation/oxidative cyanation protocol. By this method, several highly substituted indolizidine and quinolizidine architectures were constructed. Quantum mechanical DFT calculations at the B3LYP/6-31+G(d) level of theory were performed for these cyclizations and provide insights into the origins of the observed diastereoselectivities.
Iron-catalyzed intramolecular allylic C-H amination
Paradine, Shauna M.,White, M. Christina
, p. 2036 - 2039 (2012/03/11)
A highly selective C-H amination reaction under iron catalysis has been developed. This novel system, which employs an inexpensive, nontoxic [Fe IIIPc] catalyst (typically used as an industrial ink additive), displays a strong preference for allylic C-H amination over aziridination and all other C-H bond types (i.e., allylic > benzylic > ethereal > 3° > 2° ? 1°). Moreover, in polyolefinic substrates, the site selectivity can be controlled by the electronic and steric character of the allylic C-H bond. Although this reaction is shown to proceed via a stepwise mechanism, the stereoretentive nature of C-H amination for 3° aliphatic C-H bonds suggests a very rapid radical rebound step.
Palladium(II)-catalyzed cyclization of unsaturated hydroperoxides for the synthesis of 1,2-dioxanes
Harris, Jason R.,Waetzig, Shelli R.,Woerpel
supporting information; experimental part, p. 3290 - 3293 (2009/12/05)
The cyclization of γ, δ-unsaturated tertiary hydroperoxides in the presence of a palladium(II) catalyst afforded 1,2-dioxanes resembling biologically active natural products. A variety of substrates were screened, and synthetic manipulations were accomplished to construct compounds with structural similarity to antimalarial targets.
Synthesis of Quinolines and 2H-Dihydropyrroles by Nucleophilic Substitution at the Nitrogen Atom of Oxime Derivatives
Kitamura, Mitsuru,Yoshida, Masayuki,Kikuchi, Takashi,Narasaka, Koichi
, p. 2415 - 2426 (2007/10/03)
Isomerization of oxime derivatives was researched in detail to find out the methods for the syn-anti isomerization of O-substituted oximes. Based on these findings were developed simple methods for the preparation of aza-heterocycles from both stereoisomers of oximes. Quinolines were synthesized from β-aryl ketone oximes by treatment with trifluoroacetic anhydride and 4-chloranil. γ,δ-Unsaturated O-methoxyacetyloximes were transformed to 2H-dihydropyrroles by reaction with methoxy-acetic acid.
