New Ring Expansion of Cyclobutanones: Synthesis of Pyrrolinones, Pyrrolidines and Pyrroles
作者:Norbert De Kimpe、Guido Verniest、Stefaan Boterberg、Filip Bombeke、Christian V. Stevens
DOI:10.1055/s-2004-822900
日期:——
2-Dichlorocyclobutanones reacted with various amines to give ring opening leading to 4,4-dichlorobutanamides. These compounds proved to be suitable substrates for the synthesis of 3-pyrrolin-2-ones, 2-pyrrolidinones, pyrrolidines and pyrroles.
Preparation of ?,?-Dibromocyclobutanones from Olefins: A simple procedure for the regioselective functionalization of olefins
作者:H�l�ne Chaumeil、Claude Le Drian
DOI:10.1002/hlca.19960790416
日期:1996.6.26
of tribromoacetyl bromide in the presence of POCl3. Under these conditions, the cycloaddition of dibromoketene with olefins 5 yields α,α-dibromocyclobutanones 2, which are cleaved with alkoxides to yield β-dibromomethyl esters 4. Several examples are given. For monosubstituted olefins, the functionalization is regioselective, the methoxycarbonyl group being introduced at the terminal C-atom.