Access to Air‐Stable 1,3‐Diphosphacyclobutane‐2,4‐diyls by an Arylation Reaction with Arynes

Abstract

Tuning of the physicochemical properties of the 1,3diphosphacyclobutane-2,4-diyl unit is attractive in view of materials applications.T he use of arynes is shown to be effective for installing relatively electron rich aryl substituents into the open-shell singlet P-heterocyclic system. Treatment of the sterically encumbered 1,3-diphosphacyclobuten-4-yl anion with ortho-silylated aryl triflates in the presence of fluoride under appropriate conditions afforded the corresponding 1aryl 1,3-diphosphacyclobutane-2,4-diyls.T he air-stable openshell singlet P-heterocycles exhibit considerable electrondonating character,a nd the aromatic substituent influences the open-shell character,w hich is thought to be related to the property of p-type semiconductivity.T he P-arylated 1,3diphosphacyclobutane-2,4-diyl systems can be further utilized as detectors of hydrogen fluoride (HF), which causes ar emarkable changei nt heir photoabsorption properties.Scheme 1. Addition of phosphines to arynes. Scheme 2. S N Ar reaction of 1 with an electron-deficient N-heteroaryl reagent. Mes* = 2,4,6-tBu 3 C 6 H 2 .

Phosphorus(III)-assisted regioselective C–H silylation of heteroarenes

“…1c). Unlike the well-developed C-H borylation reactions, C7silylation can only resort to C7-lithiated indoles with silicon electrophiles, this process is not compatible with many sensitive functional groups [54][55][56][57] . Herein, we report a regioselective C-H silyation of indoles at C7 position using organosilane reagents enabled by Pd(OAc) 2 with oxidative conditions (Fig.…”