18595-17-0Relevant articles and documents
Chemoselectivity for Alkene Cleavage by Palladium-Catalyzed Intramolecular Diazo Group Transfer from Azide to Alkene
Frost, Grant B.,Mittelstaedt, Michaela N.,Douglas, Christopher J.
supporting information, p. 1727 - 1732 (2019/01/09)
Alkenes can be cleaved by means of the (3+2) cycloaddition and subsequent cycloreversion of 1,3-dipoles, classically ozone (O3), but the azide (R?N3) variant is rare. Chemoselectivity for these azide to alkene diazo group transfers (DGT) is typically disfavored, thus limiting their synthetic utility. Herein, this work discloses a palladium-catalyzed intramolecular azide to alkene DGT, which grants chemoselectivity over competing aziridination. The data support a catalytic cycloreversion mechanism distinct from other known metal-catalyzed azide/alkene reactions: nitrenoid/metalloradical and (3+2) cycloadditions. Kinetics experiments reveal an unusual mechanistic profile in which the catalyst is not operative during the rate-controlling step, rather, it is active during the product-determining step. Catalytic DGT was used to synthesize N-heterocyclic quinazolinones, a medicinally relevant structural core. We also report on the competing aziridination and subsequent ring expansion to another N-heterocyclic core structure of interest, benzodiazepinones.
Iodine(III) Reagent-Mediated Intramolecular Amination of 2-Alkenylanilines to Prepare Indoles
Zhao, Chun-Yang,Li, Kun,Pang, Yu,Li, Jia-Qing,Liang, Cui,Su, Gui-Fa,Mo, Dong-Liang
supporting information, p. 1919 - 1925 (2018/03/28)
A variety of 3-substituted and 2,3-disubstituted indoles were synthesized efficiently in good yields through the intramolecular amination of 2-alkenylanilines promoted by readily available iodine(III) reagents in a short reaction time. Mechanistic studies showed that the reaction pathway went through a nitrenium ion and that 3-acetoxy indoline was the key intermediate in the indole formation. The indole product was easily prepared on a gram scale and amination also proceeded smoothly using catalytic 3,5-dimethylphenyl iodine in the presence of mCPBA. Furthermore, the indolo[3,2-a]carbazole scaffold was prepared in good yield in six steps from commercial ortho-iodoaniline. (Figure presented.).
Hofmann-type rearrangement of imides by in situ generation of imide-hypervalent iodines(III) from iodoarenes
Moriyama, Katsuhiko,Ishida, Kazuma,Togo, Hideo
supporting information; experimental part, p. 946 - 949 (2012/05/05)
The Hofmann-type rearrangement of aromatic and aliphatic imides using a hypervalent iodine(III) reagent generated in situ from PhI, m-CPBA, and TsOH·H2O proceeded in the presence of a base in alcohol to provide anthranilic acid derivatives and amino acid derivatives in high yields, respectively. This reaction proceeds through a tandem reaction via alcoholysis followed by a Hofmann rearrangement promoted by the formation of an imide-λ3-iodane intermediate.