Phosphorus bonds with Group 13 compounds

In contrast to phosphorus esters, sulfur esters are usually cleaved at the carbon-oxygen bond with carbon-fluorine bond formation Cleavage of esteri nf methanesulfonic acid, p-toluenesidfonic acid, and especially trifluoromethane-sulfonic acid (tnflic acid) by fluoride ion is the most widely used method for the conversion of hydroxy compounds to fluoro derivatives Potassium fluoride, triethylamine trihydrofluoride, and tetrabutylammonium fluoride are common sources of the fluoride ion For the cleavage of a variety of alkyl mesylates and tosylates with potassium fluoride, polyethylene glycol 400 is a solvent of choice, the yields are limited by solvolysis of the leaving group by the solvent, but this phenomenon is controlled by bulky substituents, either in the sulfonic acid part or in the alcohol part of the ester [42] (equation 29)... 

The magnetic criterion is particularly valuable because it provides a basis for differentiating sharply between essentially ionic and essentially electron-pair bonds Experimental data have as yet been obtained for only a few of the interesting compounds, but these indicate that oxides and fluorides of most metals are ionic. Electron-pair bonds are formed by most of the transition elements with sulfur, selenium, tellurium, phosphorus, arsenic and antimony, as in the sulfide minerals (pyrite, molybdenite, skutterudite, etc.). The halogens other than fluorine form electron-pair bonds with metals of the palladium and platinum groups and sometimes, but not always, with iron-group metals. 

Functionally substituted phosphines play an important role as ligands in a great variety of phosphorus coordination compounds. They have some interesting features that distinguish them from other phosphine ligands, namely (a) the presence of other heteroatoms bearing lone electron pairs in addition to phosphorus (b) the presence of functional groups able to form bonds with a metal with the participation of its valence electrons ... 

The resistance of the E14-S bond in cyclotrimetallathianes toward nucleophilic reagents, for example, water and alcohol,62 increases on going from the silicon compounds to the corresponding germanium and tin derivatives. This is due, most likely, to the fact that the reaction of less nucleophilic ylides with phenyl groups at the phosphorus atom with trithianes (R2MS)3 (M = Ge, Sn) occurs slowly and is impeded by several side processes. 

We begin, however, with a brief consideration of a group of phosphorus compounds of significance for their utility in the formation of carbon-phosphorus bonds via reaction with organometallic reagents in displacement reactions. 

The 3-phospholene 1-oxide derivative is a potential heterocycle for easily producing chemically modified phosphorus heterocycles because the compound possesses a reactive C=C double bond, allylic methylene, an electron-deficient methylene group a-positioned to phosphorus, etc. 4-Chloro-l,6-dihydrophosphinie derivatives 16A and 16B are prepared from dichloro-carbene adducts 15 with l-(R)-3-ethylphospholene 1-oxide (Scheme 5) [4]. 

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