Triphenylstannyl anion

The crystal structure of triphenylstannylpotassium-[18]ane06, [Ph3Sn] [KCllSJaneOg)], where [ISJaneOs is the crown ether [18]crown-6 cyclo-(-OCH2CH2-)6 shows that the units in the crystal are crown ether-potassium ion complexes and pyramidal triphenylstannyl anions. The Mossbauer spectrum of this solid consists of a quadrupole-split doublet (5 2.17 mm s , ... 

Photonucleophilic aromatic substitution reactions of phenyl selenide and telluride with haloarenes have also been proven to involve the S jlAr mechanism, with the formation of anion radical intermediates. Another photonucleophihc substitution, cyanomethylation, proves the presence of radical cations in the reaction mechanism. Liu and Weiss have reported that hydroxy and cyano substitution competes with photo substitution of fluorinated anisoles in aqueous solutions, where cation and anion radical intermediates have been shown to be the key factors for the nucleophilic substitution type. Rossi et al. have proposed the S j lAr mechanism for photonucleophihc substitution of carbanions and naphthox-ides to halo anisoles and l-iodonaphthalene. > An anion radical intermediate photonucleophilic substitution mechanism has been shown for the reactions of triphenyl(methyl)stannyl anion with halo arenes in liquid ammonia. Trimethylstannyl anion has been found to be more reactive than triphenylstannyl anion in the photostimulated electron- transfer initiation step. 

If the ligand X2 in a pentacoordinate triorganotin compound is potentially bidentate, such as the anion of l,3-diphenyl-l,3-propanedione or ofiV-benzoyl-N-phenylhydroxylamine, the tin atom is constrained to a cis-RsSnXj type of geometry, e.g., the triphenylstannyl derivatives of... 

The reaction of trimethyl and triphenylstannyl potassium with mono- and di-substituted enones in acetonitrile as solvent led in nearly quantitative yields either to a mixture of diastereomers or to a pure diastereomer of /S-stannylketones (Scheme 41)109. There was experimental support for the existence of a SET mechanism, i.e. partial or total inhibition of the reaction by addition of a free radical scavenger (galvinoxyl) or a radical anion scavenger (p-dinitrobenzene). The possibility of a SET depends on the one-electron donor ability of the nucleophile and the electron acceptor ability of the ketone. These reactions are stereoselective. 

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