58138-81-1Relevant academic research and scientific papers
Photocatalyzed Triplet Sensitization of Oximes Using Visible Light Provides a Route to Nonclassical Beckmann Rearrangement Products
Zhang, Xiao,Rovis, Tomislav
, p. 21211 - 21217 (2021/12/27)
Oximes are valuable synthetic intermediates for the preparation of a variety of functional groups. To date, the stereoselective synthesis of oximes remains a major challenge, as most current synthetic methods either provide mixtures of E and Z isomers or furnish the thermodynamically preferred E isomer. Herein we report a mild and general method to achieve Z isomers of aryl oximes by photoisomerization of oximes via visible-light-mediated energy transfer (EnT) catalysis. Facile access to (Z)-oximes provides opportunities to achieve regio- and chemoselectivity complementary to those of widely used transformations employing oxime starting materials. We show an enhanced one-pot protocol for photocatalyzed oxime isomerization and subsequent Beckmann rearrangement that enables novel reactivity with alkyl groups migrating preferentially over aryl groups, reversing the regioselectivity of the traditional Beckmann reaction. Chemodivergent N- or O- cyclizations of alkenyl oximes are also demonstrated, leading to nitrones or cyclic oxime ethers, respectively.
Iron-Catalyzed Ortho C-H Methylation of Aromatics Bearing a Simple Carbonyl Group with Methylaluminum and Tridentate Phosphine Ligand
Shang, Rui,Ilies, Laurean,Nakamura, Eiichi
supporting information, p. 10132 - 10135 (2016/08/31)
Iron-catalyzed C-H functionalization of aromatics has attracted widespread attention from chemists in recent years, while the requirement of an elaborate directing group on the substrate has so far hampered the use of simple aromatic carbonyl compounds such as benzoic acid and ketones, much reducing its synthetic utility. We describe here a combination of a mildly reactive methylaluminum reagent and a new tridentate phosphine ligand for metal catalysis, 4-(bis(2-(diphenylphosphanyl)phenyl)phosphanyl)-N,N-dimethylaniline (Me2N-TP), that allows us to convert an ortho C-H bond to a C-CH3 bond in aromatics and heteroaromatics bearing simple carbonyl groups under mild oxidative conditions. The reaction is powerful enough to methylate all four ortho C-H bonds in benzophenone. The reaction tolerates a variety of functional groups, such as boronic ester, halide, sulfide, heterocycles, and enolizable ketones.
Palladium-Catalyzed Reaction of Acyliron Complexes with Aryl Halydes. A Convenient Synthesis of Aromatic Ketones
Koga, Teruyoshi,Makinouchi, Shinako,Okukado, Nobuhisa
, p. 1141 - 1144 (2007/10/02)
Acyliron complexes, easily prepared from disodium tetracarbonylferrate and alkyl halides, reacted with aryl iodides in the presence of a catalytic amount of Pd(PPh3)4 and a cocatalyst, ZnCl2, to give aromatic ketones in good yields. (R)-2-Methyl-1-phenyl-octanone was prepared starting from (S)-2-bromooctane in an excellent optical yield.
