Contrasting Frustrated Lewis Pair Reactivity with Selenium‐ and Boron‐Based Lewis Acids. Issue 37 (3rd August 2016)

• Record Type: Journal Article
• Authors: Wilkins, Lewis C.; Günther, Benjamin A. R.; Walther, Melanie; Lawson, James R.; Wirth, Thomas; Melen, Rebecca L.
• Is Part Of: Angewandte Chemie international edition. Volume 55:Issue 37(2016)
• Page Start: 11292
• Page End: 11295
• Publication Date: 2016-08-03
• Subjects: annulation -- cyclization -- domino reactions -- frustrated Lewis pairs -- main-group elements; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201605239
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: The activation of π‐bonds in diynyl esters has been investigated by using soft and hard Lewis acids. In the case of the soft selenium Lewis acid PhSeCl, sequential activation of the alkyne bonds leads initially to an isocoumarin (1 equiv PhSeCl) and then to a tetracyclic conjugated structure with the isocoumarin subunit fused to a benzoselenopyran (3 equiv PhSeCl). Conversely, the reaction with the hard Lewis acidic borane B(C6 F5 )3 initiates a cascade reaction to yield a complex π‐conjugated system containing phthalide and indene subunits. Abstract : Making a difference : The activation of π‐bonds in diynyl esters by soft and hard Lewis acids has been investigated in a one‐pot reaction. The soft selenium reagent PhSeCl affords a salt containing three distinct selenium environments, while the hard Lewis acid borane B(C6 F5 )3 yields a complex conjugated zwitterionic system in a domino reaction.