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Updated: Jun 3, 2026

Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides
Published on: May 26, 2019
Synthesis of polyfunctional allenes by successive copper-mediated substitutions
Matthias A Schade1, Shigeyuki Yamada, Paul Knochel
1Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, 81377 München, Germany.
Abstract:
Readily available 1,1-dichloro-2-alkynes are versatile starting materials for the synthesis of polyfunctionalized allenes. They can be prepared from commercially available terminal alkynes in a two-step procedure. The Cu-mediated reaction of several 1,1-propargylic derivatives with functionalized alkyl, benzylic, or allylic zinc reagents proceeds exclusively with S(N)2' selectivity and allows a rapid and efficient synthesis of functionalized chloroallenes. These chloroallenes undergo a novel Cu(I) -catalyzed substitution reaction with functionalized arylmagnesium reagents with excellent S(N)2 selectivity to give trisubstituted polyfunctionalized allenes. The functional group tolerance is excellent and functionalities, such as cyano, keto, ester, phosphate, trifluoromethyl, and halogens, are well tolerated.
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