Enantioselective Annulations for Dihydroquinolones by in Situ Generation of Azolium Enolates
作者:Anna Lee、Ashkaan Younai、Christopher K. Price、Javier Izquierdo、Rama K. Mishra、Karl A. Scheidt
DOI:10.1021/ja505880r
日期:2014.7.30
A convergent, catalytic asymmetric formal [4 + 2] annulation for the synthesis of dihydroquinolones has been developed. Carboxylic acids can be employed as precursors to NHC enolates through an in situ activation strategy. Simultaneous generation of a reactive aza-o-quinone methide under the basic conditions employed for NHC generation leads to a dual activation approach.
Lewis Base and Brønsted Base Dual-Catalyzed Formal [4+3] Cycloaddition Reaction: Synthesis of Aza-Spirocycloheptane Oxindole
An intermolecular, quaternary carbon center forming [4+3] cycloaddition reaction catalyzed by Lewis base and Bronsted base has been successfully developed. The dual catalysis exhibits a superior ability to enable a previously challenging reaction, and the corresponding quaternary aza-spirocycloheptane oxindole scaffolds are efficiently synthesized with moderate to high yields.
DMAP-Catalyzed [4+3] Spiroannulation of Pyrazolone-Derived Morita–Baylis–Hillman Carbonates with <i>N</i>-(<i>o</i>-Chloromethyl)aryl Amides to Forge Spiro[pyrazolone-azepine] Scaffolds
作者:Xingfu Wei、Yue Huang、Zahra Karimi、Jingping Qu、Baomin Wang
DOI:10.1021/acs.joc.3c00262
日期:2023.7.21
Synthesis of functionalized spiro[indanone-benzazepine] scaffolds via [4 + 3] annulation reaction of N-(o-chloromethyl)aryl amides with ninhydrin-derived Morita−Baylis−Hillman carbonates