Pawel Fludzinski

Insect antifeedant elemanolide lactones from Vernonia amygdalina

Abstract Chemical investigation of insect antifeedants from the bitter tasting leaves of Vernonia amygdalina by the application of semi-preparative reversed

Chloroacetylenes as Michael acceptors. I. mechanism of enolate dichlorovinylation.

Abstract The condensation of certain enolates with trichloroethylene to yield α-dichlorovinyl ketones has been shown to proceed by way dichloroacetylene as an obligatory intermediate.

Chloroacetylenes as Michael acceptors. II. Direct ethynylation and vinylation of tertiary enolates.

Abstract The reaction of ClCCCl, PhCCCl and PhSCCCl with a variety of tertiary enolates leads in 43–90% yields to α-chloroethynyl, α-phenylethynyl and α-thiophenylethynyl derivatives. The −CCCl group is smoothly converted to −CCH using copper powder in HOAc/THF, or is directly reduced (H 2 /Lindlar catalyst) to the −CHCH 2 group, thus providing facile access to many α-ethynyl and α-vinyl ketones and esters.

The dichlorovinylation of enolates

Abstract The condensation of certain ketone and ester enolates with trichloroethylene proceeds with surprising ease to yield dichlorovinylation products. The trans stereochemistry for one such product is established by X-ray, and subsequent transformations of these initial products to ethinyl or ω-chloroethinyl derivatives is described.