title: Frustrated Lewis Pair-Catalyzed Cycloisomerization of 1,5-Enynes via a 5-endo-dig Cyclization/Protodeborylation Sequence.
abstract: The first frustrated Lewis pair-catalyzed cycloisomerization of a series of 1,5-enynes was developed. The reaction proceeds via the π-activation of the alkyne and subsequent 5-endo-dig cyclization with the adjacent alkene. The presence of PPh3 was of utmost importance on the one hand to prevent side reactions (for example, 1,1-carboboration) and on the other hand for the efficient protodeborylation to achieve the catalytic turnover. The mechanism is explained on the basis of quantum-chemical calculations, which are in full agreement with the experimental observations.
authors.affiliation: Institute of Organic Chemistry, University of Paderborn, Warburger Strasse 100, 33098, Paderborn, Germany.
authors.forename: Sergej
authors.initials: S
authors.lastname: Tamke
authors.affiliation: Mulliken Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie, University of Bonn, Beringstrasse 4, 53115, Bonn, Germany.
authors.forename: Zheng-Wang
authors.initials: ZW
authors.lastname: Qu
authors.affiliation: Institute of Organic Chemistry, University of Paderborn, Warburger Strasse 100, 33098, Paderborn, Germany.
authors.forename: Nikolai A
authors.initials: NA
authors.lastname: Sitte
authors.affiliation: Institute of Inorganic and Analytical Chemistry, University of Paderborn, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Flörke
authors.affiliation: Mulliken Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie, University of Bonn, Beringstrasse 4, 53115, Bonn, Germany. grimme@thch.uni-bonn.de.
authors.forename: Stefan
authors.initials: S
authors.lastname: Grimme
authors.affiliation: Institute of Organic Chemistry, University of Paderborn, Warburger Strasse 100, 33098, Paderborn, Germany. jan.paradies@uni-paderborn.de.
authors.forename: Jan
authors.identifier: http://orcid.org/0000-0002-3698-668X
authors.initials: J
authors.lastname: Paradies
keywords: 1,5-enynes; cycloisomerization; frustrated Lewis pairs; kinetic isotope effect; protodeborylation