5376-55-6Relevant articles and documents
C2-Alkenylation of N-heteroaromatic compounds: Via Br?nsted acid catalysis
Crisenza, Giacomo E. M.,Dauncey, Elizabeth M.,Bower, John F.
supporting information, p. 5820 - 5825 (2016/07/06)
Substituted heteroaromatic compounds, especially those based on pyridine, hold a privileged position within drug discovery and medicinal chemistry. However, functionalisation of the C2 position of 6-membered heteroarenes is challenging because of (a) the difficulties of installing a halogen at this site and (b) the instability of C2 heteroaryl-metal reagents. Here we show that C2-alkenylated heteroaromatics can be accessed by simple Br?nsted acid catalysed union of diverse heteroarene N-oxides with alkenes. The approach is notable because (a) it is operationally simple, (b) the Br?nsted acid catalyst is cheap, non-toxic and sustainable, (c) the N-oxide activator disappears during the reaction, and (d) water is the sole stoichiometric byproduct of the process. The new protocol offers orthogonal functional group tolerance to metal-catalysed methods and can be integrated easily into synthetic sequences to provide polyfunctionalised targets. In broader terms, this study demonstrates how classical organic reactivity can still be used to provide solutions to contemporary synthetic challenges that might otherwise be approached using transition metal catalysis.
Acid-Catalyzed Nitronate Cycloaddition Reactions. Useful Syntheses and Simple Transformations of 3-Acyl- and 3-Alkenylisoxazolines
Wade, Peter A.,Amin, Nayan V.,Yen, Hwa-Kwo,Price, David T.,Huhn, George F.
, p. 4595 - 4601 (2007/10/02)
Nitronic esters derived from primary nitro ketones, ethyl nitroacetate, and (phenylsulfonyl)nitromethane react with dipolarophiles in the presence of nonaqueous protic and Lewis acids to give nitrile oxide cycloadducts. α-Nitro ketones, ethyl nitroacetate
