Synthesis of Chalcogen-Substituted Phosphiranes: A Privileged Phosphinidene Precursor

A simple and convenient method for synthesizing chalcogen-substituted (Ch = S or Se) phosphiranes was achieved through the reaction of a phosphiranide complex with sulfur (or selenium). The presented approach shows a good functional group compatibility. The ring strain and stability of the lone pair of S (or Se) on phosphinidenes enable these phosphiranes to be privileged phosphinidene precursors. The synthetic potentials of these chalcogen-substituted phosphiranes were demonstrated through P-S (Se) bond transfer reactions with various phosphinidene trapping reagents.

Phosphirane-Enabled Synthesis of Aromatic 1H-1,2-Azaphospholes and Phosphinines

Aromatic heteroarenes are essential components of numerous valuable molecules. Herein we present a simple and effective route to access aromatic 1H-1,2-azaphospholes and phosphinines. This method utilizes the ring tension of phosphiranes to convert simple β-chloroethylphosphane and alkynyl imines into these valuable compounds. The nucleophilic addition of the phosphiranide complex to alkynyl imines results in phosphiranes 3, which transform into 1H-1,2-azaphospholes under mild conditions. The skeletal editing of 1,2-azaphospholes into phosphinine derivatives was accomplished through a cascade process involving a [4 + 2] cycloaddition and the elimination of a nitrogen moiety.

Construction of central and axial chirality via Pd(II)/Bim-catalyzed asymmetric dearomative Michael reaction of polycyclic tropones

A highly enantioselective Pd/Bim-catalyzed dearomative Michael reaction applying polycyclic tropones as non-benzenoid aromatic Michael acceptors and arylboronic acids as aryl pronucleophiles has been developed. The bridged biaryls bearing central and axial chirality, including pentacyclic cyclohepta[b]indoles and 6,7-dihydrodibenzo[a,c][7]annulen-5-ones, are generally generated in good to high yields and excellent enantioselectivities and can be readily transformed into useful derivatives.

Advancement in Synthetic Strategies of Phosphorus Heterocycles: Recent Progress from Synthesis to Emerging Class of Optoelectronic Materials

Organophosphorus heterocycles have long been acknowledged for their significant potential across diverse fields, including catalysis, material science, and drug development. Incorporating phosphorus functionalities into organic compounds offers a means to effectively tailor their medicinal properties, augment biological responses, and enhance selectivity and bioavailability. The distinctive physical and photoelectric characteristics of phosphorus-containing conjugated compounds have garnered considerable interest as promising materials for organic optoelectronics. These compounds find extensive utility in various applications such as light-emitting diodes, photovoltaic cells, phosphole-based fluorophores, and semiconductors.

BF3-Promoted Ring Expansion of Iminylphosphiranes and Acylphosphiranes for Divergent Access to 1,2-Azaphospholidines and 1,2-Dihydrophosphetes

Ring expansion of strained small rings provides an efficient method for the synthesis of various high-value carbocycles and heterocycles. Here we report BF3·Et2O as both an activating reagent and fluorine source, enabling ring expansion of phosphirane and P-F bond formation. Treatment of 1-iminylphosphirane complexes with BF3·Et2O resulted in 1,2-azaphospholidines, while the reaction of 1-acylphosphirane complexes with BF3·Et2O afforded 1,2-dihydrophosphetes. The reaction path was tuned by the nucleophilicity of the N and O atoms toward the intermediate phosphenium cation.

Phosphorus-Involved Wagner-Meerwein Rearrangement of Phosphiranes: An Entry to Four-Membered Phosphacycles

Phosphenium ions [R₂P]⁺ are important and highly reactive dicoordinate phosphorus species. Herein, we report a rearrangement of the carbocation into the phosphenium cation driven by ring strain. This phosphorus-involved Wagner-Meerwein rearrangement pathway converted the 1-acylphosphirane complex into phosphetane and 1,2-dihydrophosphete derivatives depending on the reaction temperature. The generation of the intermediate phosphenium cation was identified by the intramolecular reaction with ether, which also disclosed its strong Lewis acidity. This work expands the boundary of the phosphorus-carbon analogy.

Annulation of phosphole sulfides via [3 + 2] cycloaddition with nitrones

We developed a facile pathway for the construction of the phospholene fused isoxazolidine skeleton through the [3 + 2] cycloaddition reaction of phosphole sulfides.