title: Unusual coupling reactions of aldehydes and alkynes: a novel preparation of substituted phthalic acid derivatives by automated synthesis.
abstract: Based upon a highly versatile multicomponent methodology, a new one-pot synthesis of substituted phthalic acid derivatives from alpha,beta-unsaturated aldehydes was developed. The reaction involves the intermediacy of an acetamidodiene species which undergoes Diels-Alder addition to diethyl acetylenedicarboxylate. The resultant acetamidocyclohexadiene is subject to elimination of acetamide under the reaction conditions to give rise to substituted diethyl phthalates in good yields. This domino condensation-cycloaddition-elimination sequence has been applied to a variety of alpha,beta-unsaturated aldehydes. Furthermore, we demonstrated the exploitation of parallelized and automated synthesis technology for the rapid screening of reaction conditions and compositions. Detailed studies revealed the catalytic role of the employed acetamide and the occurrence of a stereoselective 1,4-syn elimination pathway under standard conditions.
authors.affiliation: Leibniz-Institut für Organische Katalyse an der Universität Rostock e V, Buchbinderstrasse 5-6 18055 Rostock, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Jacobi von Wangelin
authors.forename: Helfried
authors.initials: H
authors.lastname: Neumann
authors.forename: Dirk
authors.initials: D
authors.lastname: Gördes
authors.forename: Stefan
authors.initials: S
authors.lastname: Klaus
authors.forename: Haijun
authors.initials: H
authors.lastname: Jiao
authors.forename: Anke
authors.initials: A
authors.lastname: Spannenberg
authors.forename: Thomas
authors.initials: T
authors.lastname: Krüger
authors.forename: Christian
authors.initials: C
authors.lastname: Wendler
authors.forename: Kerstin
authors.initials: K
authors.lastname: Thurow
authors.forename: Norbert
authors.initials: N
authors.lastname: Stoll
authors.forename: Matthias
authors.initials: M
authors.lastname: Beller