[4 + 1]- and [4 + 2]-cycloadditions of a thiazole-2-thione-based 1,4-diphosphinine - broadening the scope
Tim Kalisch1, Gregor Schnakenburg1, Georgii I Nikonov2
1Institute of Inorganic Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Straße 1, 53123 Bonn, Germany. r.streubel@uni-bonn.de.
Abstract:
A broad study on [4 + 1]- and [4 + 2]-cycloaddition reactions of a thiazole-2-thione-based 1,4-diphosphinine (1) is reported, with a special focus on reversible reactions. Reactions of 1 with group 13 carbenoids DippNacNacM (M = Al and Ga) afford [4 + 1] adducts that can be classified as Al and Ga phosphides or as 7-metalla-1,4-norbornadienes. Reactions of 1 with alkynes and alkenes result in [4 + 2]-cycloaddition, affording 1,4-diphosphabarrelenes. The effect of different dienophiles on the formation of 1,4-diphosphabarrelenes and their thermal [4 + 2]-cycloreversion reactions is studied from an experimental as well as theoretical point of view, opening the door for protection/deprotection strategies in this chemistry.
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