67759-79-9Relevant 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.
Studies on the Benzoxazine Series. 2- Preparation and 1H and 13C NMR Structural Study of Some Substituted 1,2-Dihydro-4H-3,1-benzoxazines
Neuvonen, Kari,Pohtola, Riitta,Pihlaja, Kalevi
, p. 725 - 733 (2007/10/02)
In addition to the parent compounds, nine methyl-substituted 1,2-dihydro-4H-3,1-benzoxazines with and without N-methyl substitution were prepared.The chain tautomer could only be detected in the case of 1,2-dihydro-2-(p-nitrophenyl)-4H-3,1-benzoxazine in
Alkaloid synthesis via the intramolecular imidate methylide 1,3-dipolar cycloaddition reaction
Smith, Richard,Livinghouse, Tom
, p. 3559 - 3568 (2007/10/02)
A concise synthesis for the neurotoxic physostigmine alkaloid d,l-eserethole is described which relys upon an intramolecular cycloaddition reaction involving a "non-stabilized" imidate methylide and an unactivated alkene. The facility of this cyclization