Cyclic‐Phenoxaphosphinine‐Based Mixed Phosphonium‐Iodonium Ylides with Electron‐Withdrawing Substituents – Synthesis and Structural FeaturesстатьяИсследовательская статья
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Аннотация:A series of phosphonium ylides and mixed phosphonium-iodonium ylides based on cyclic phenoxaphosphinine has been synthesized, representing a new structural type of ylides. The influence of the electron-withdrawing substituents of various nature on the stability and physicochemical properties of phenoxaphosphonium ylides is discussed. Our findings reveal a progressive reduction in ylide stability as the carbonyl group is replaced first with a phosphonate group and then with a nitrile group. NMR data indicates that the presence of a cyclic phosphonium group results in a lowered energy barrier to rotation about the carbon-carbon bond, both in phosphonium and mixed phosphonium-iodonium ylides with α-carboxyl substituents when compared to triarylphosphonium ylides. These experimental results are further supported and analyzed in the context of density functional theory (DFT) calculations.
