Annelated P-containing heterocycles from aryl- and hetaryl-substituted phosphonium iodonium ylides with a methoxycarbonyl-group

Phenoxaphosphonium Mixed Ylides in Ring Expansion Reaction

Treatment of mixed phosphonium-iodonium ylides featuring a six-membered phenoxaphosphonium fragment with aqueous tetrafluoroboronic acid induces a rearrangement, resulting in expansion of the phosphacycle and oxidation of the phosphorus atom. The target difficult-to-access dibenzo[b,f][1,4]oxaphosphepine oxides (3 examples) were isolated in excellent yields (up to 95%) as mixtures of stereoisomers. Hydrolysis of a five-membered mixed ylide, a dibenzophosphole derivative, predominantly preserves the phosphole system with cycle expansion occurring as a side process.

CIDNP as a tool to unveil the reaction mechanism: interaction of mixed phosphonium–iodonium ylide withp-methoxyphenylacetylene

In situ acquisition of the reaction between benzoyl phosphonium–iodonium ylide and p-methoxyphenylacetylene in an NMR spectrometer reveals the CIDNP effect in ³¹P and ¹H NMR spectra of major products, substituted furan (emission) and phosphonium salt (enhanced absorption). The mechanism of products formation via radical pairs is discussed.

CIDNP in ³¹P NMR spectra of major products in the course of the reaction between phosphonium–iodonium ylide and p-methoxyphenylacetylene reveals the mechanism of products formation via radical pair.

Synthesis and Photophysical Properties of λ5-Phosphinines as a Tunable Fluorophore

A practical synthesis of a variety of λ⁵-phosphinines, which show distinct fluorescence both in solution and solid state, is described. Both C4-selective electrophilic substitutions and the following conversions realized an easy preparation of a wide range of derivatives having several substituents for electronic modification, which provides the potential for fine-tuning of the photophysical properties.