MgI<sub>2</sub>-Mediated Ring Expansions of Secondary Methylenecyclopropyl Amides
作者:Mark Lautens、Wooseok Han、Jack Hung-Chang Liu
DOI:10.1021/ja028967l
日期:2003.4.1
Ring expansion of secondary methylenecyclopropyl amides in the presence of MgI2 was investigated. Various isomeric five-membered unsaturated lactams were obtained, depending on the character of the substituent Q. The amide group served as a nucleophile in ring closing as well as an activator for ring opening. In the presence of a variety of aryl aldimines or aldehydes, alkylative ring expansion occurred in a single step under mild and neutral conditions leading to gamma'-amino- or -hydroxy-alkylated pyrrol-2-ones. Also, it was shown that a 4-methylpyrrol-2-one could be transformed to a gamma-hydroxy-alkylated product by the use of a direct vinylogous aldol reaction.
Synthesis of β,γ-Unsaturated Lactams via a Magnesium Iodide Promoted Ring Expansion of Secondary Methylenecyclopropyl Amides
作者:Mark E. Scott、Christina A. Schwarz、Mark Lautens
DOI:10.1021/ol0621957
日期:2006.11.1
A novel and efficient route to exo-beta,gamma-unsaturated lactams from substituted and non-substituted secondary methylenecyclopropyl amides is reported. Subsequent modification of the resulting exo-beta,gamma-unsaturated lactams provides access to several pharmaceutically relevant scaffolds. [reaction: see text].