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Preparation and Reactivity of a Triphosphenium Bromide Salt: A Convenient and Stable Source of PhosphorusI
Published on: November 22, 2016
Novel Five- and Six-Membered Rings of Phosphorus-Selenium Heterocycles from Selenation of Amido-Schiff Bases
Guoxiong Hua1, David B Cordes1, Alexandra M Z Slawin1
1EaStCHEM School of Chemistry, University of St Andrews, Fife KY16 9ST, U.K.
Abstract:
Woollins' reagent, [2,4-bis(phenyl)-1,3-diselenadiphosphetane-2,4-diselenide], serving as a selenating-reductive cycloaddition reagent, reacts with nonconjugated amido-Schiff bases to give the corresponding six-membered 1,3,4-selenadiazoles via a ring-expansion accompanied by an additional selenation/cyclization to the imine bond and C=O group; meanwhile, under the same reaction conditions, the selenation of conjugated amido-Schiff bases leads to a series of fused heterocycles with two five-membered rings. Eight single-crystal X-ray structures confirming the formation of these five- and six-membered heterocycles are discussed.
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