b-Chlorovinyl ketones are readily available from the stereoselective Friedel-Crafts acylation of terminal alkynes. While the direct nucleophilic substitution of the b-chlorine atom of b-chlorovinyl ketones has been known for sometimes, the full synthetic potential of b-chlorovinyl ketones is yet to be explored due to the lack of mechanistic understanding of the reactivity pattern of b-chlorovinyl ketones. Recently, we discovered a soft vinyl enolization method of (E)-b-chlorovinyl ketones using a mild base, NEt3, resulting in the formation of [3]cumulenolates. Subsequently, we demonstrated the nucleophilic character of [3]cumulenolates in aldol and aldol condensation reactions. Further studies on the reactivity pattern of [3]cumulenolates now suggest that the [3]cumulenolates can act as an electrophile under a diverse array of Lewis acid. In this poster, we will discuss the origin of the electrophilicity of [3]cumulenolates in the context of conjugate addition reactions.

b-Chlorovinyl ketones as both nucleophilic and electrophilic species under Lewis catalysis

246th National Meeting (2013)

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