Organotin reactants

By comparison, the products derived from monohalo, dihalo and trihalo-organotin reactants exhibit initial softening (both through visual observation utilizing the Fisher-Johns and DSC) in the range of 40 to 140 c. 

Nonaqueous two-phase systems employ two liquids that are largely immiscible in one another, such as dissolving the Lewis base in acetonitrile, nitrobenzene, or 2,5-hexadione and the acid chloride, here the organotin reactant, in a nonpolar organic liquid such as hexane, decane, or carbon tetrachloride. 

The synthetic procedures are general giving products using organotin trichlorides, diorganotin dichlorides, triorganotin chlorides and tin II and tin IV. Sample results appear in Table 2. The molar ratio of tin-containing reactant was based on the assumption that all of the active sites of the reactants would be reacted. 

While die above reactions represent only a small fraction of die reactions known for palladium, they form the basis of a powerful methodology for building carbon structures. Several variations have been developed which utilize certain types of reactants and give particular types of products. All diese variations, however, contain a common theme. In each case an electron-deficient reagent (e.g., a vinyl halide or aromatic triflate) reacts with an election-rich reagent (e.g., an alkene, an organoborane, or an organotin) witii the formation of a new carbon-carbon bond. In that sense diese reactions are related to die reactions between carbon nucleophiles and carbon electrophiles discussed previously in diis chapter. They are quite different, however, because diey proceed only in the presence of Pd(0). In fact they proceed only in die coordination sphere of Pd(0). The ability of Pd(0) to catalyze diese reactions is nearly unique We will now examine some of die more common processes. 

It is known that the geometries of the reactants play an important role in the regio-and stereochemical outcome of radical reactions since they are commonly involved in early transition states. Previous attempts to affect rotamer populations during the reaction included, among others, control of temperature and addition of a Lewis acid. It was recently reported75 that organotin halides, common byproducts of radical reactions, act... 

By appropriate choice of the reactants and the reaction conditions, a phenol-substituted carboxylic acid may react with an organotin compound to give both an organotin ester and an organotin aryl oxide within the same molecule. The reaction of trimethyltin chloride with 4-hydroxy-3-methoxybenzoic acid (HVAH) in the presence of water and pyridine at 130 °C in a sealed tube gave the unique two-dimensional coordination polymer 134 (equation 2)286. 

Organotin esters of the oxy- and thio-acids of phosphorus can be prepared inter alia by azeotropic dehydration of a mixture of the organotin hydroxide or oxide and the acid, or by treating a tin alkoxide or tin amide with the acids, or an organotin halide with a salt of the phosphorus acid. By using different molecular ratios of the reactants, products of different compositions can be obtained. Attempts to prepare phosphites may result in an Arbuzov rearrangement to a phosphorus(V) compound (e.g. equation 13-11).47... 

The 1,3,2-dioxastannacycloalkanes can be prepared by the usual routes to organotin alkoxides, but whereas simple alcohols react with diorganotin oxides only to the stage of the distannoxanes (R 0)R2Sn0SnR2(0R ), 1,2-diols react further to give the dioxastannolanes (equation 14-41).61 62 The reactions proceed much more quickly (typically in 4 to 9 min) if the reactants are heated in a microwave oven.63 Similar reactions can be carried out with dialkyltin dihalides64 and, under milder conditions, with dialkyltin dialkoxides.65-67... 

The organotin thiolates (mercaptides) are usually prepared by substitution by a sulfur nucleophile at a tin centre. Suitable pairs of reactants are (1) thiol and tin oxide, alkox-ide, or amide, (2) thiol and tin halide in the presence of a base such as sodium hydroxide, sodium carbonate, ammonia, or triethylamine, or (3) metal thiolate and tin halide. Examples are shown in equations 17-20,33 17-21,33 and 17-22,34 and some of the common products are listed in Table 17-2. 

Reactions involving organotin hydrides, or allyltin compounds, or hexaalkyldistannanes as reactants, and stannyl radicals as intermediates, now hold an important place in organic synthesis, to the degree that this dominance of organotin reagents in mediating free radical reactions has been referred to as the tyranny of tin.4... 

In order to better understand the catalytic mechanism of organotin complexes, the possibility of the ligand exchange between reactants and DBTDL was studied using IR spectroscopy. 

We have also initiated MUssbauer spectroscopic studies of photochemical reactions of inorganic and organometallic compounds (iron chelate complexes, iron carbonyl and organotin compounds) isolated in low temperature matrices. Such systems provide a complimentary approach to solid-phase photochemistry since the reaction mechanisms may be simplified by isolating the reactant molecules in inert matrices (light transmission through the reactant is also facilitated by diluting tlie colored reactant with a transparent medium). Furthermore, we have a hope for the possible outcome of such studies — their application to syntheses of novel species which may be unstable at ordinary temperatures, unless trapped in inert matrices. 

Uses Catalyst for Ziegler-Natta polymerization of olefins and dienes reactant in prod, of transition metal catalysts alkylating agent for prod, of organotin compds. and organophosphorus derivs. organic synthesis Manuf./Distrib. Akzo Nobel http //WWW. akzonobei. com Diethylaluminum chloride CAS 96-10-6 EINECS/ELINCS 202-477-2 UN UN 3052... 

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