Polymeric Grignard reagents

For the initiation of caprolactam polymerization, Grignard reagents [173] have been used as a source of lactamate salt. Tsuchiya and Tsuruta have described an interesting case of methyloxirane polymerization initiated with... 

Miscellaneous Reactions. Sodium bisulfite adds to acetaldehyde to form a white crystalline addition compound, insoluble in ethyl alcohol and ether. This bisulfite addition compound is frequendy used to isolate and purify acetaldehyde, which may be regenerated with dilute acid. Hydrocyanic acid adds to acetaldehyde in the presence of an alkaU catalyst to form cyanohydrin the cyanohydrin may also be prepared from sodium cyanide and the bisulfite addition compound. Acrylonittile [107-13-1] (qv) can be made from acetaldehyde and hydrocyanic acid by heating the cyanohydrin that is formed to 600—700°C (77). Alanine [302-72-7] can be prepared by the reaction of an ammonium salt and an alkaU metal cyanide with acetaldehyde this is a general method for the preparation of a-amino acids called the Strecker amino acids synthesis. Grignard reagents add readily to acetaldehyde, the final product being a secondary alcohol. Thioacetaldehyde [2765-04-0] is formed by reaction of acetaldehyde with hydrogen sulfide thioacetaldehyde polymerizes readily to the trimer. 

Whereas sulfolane is relatively stable to about 220°C, above that temperature it starts to break down, presumably to sulfur dioxide and a polymeric material. Sulfolane, also stable in the presence of various chemical substances as shown in Table 2 (2), is relatively inert except toward sulfur and aluminum chloride. Despite this relative chemical inertness, sulfolane does undergo certain reactions, for example, halogenations, ting cleavage by alkah metals, ring additions catalyzed by alkah metals, reaction with Grignard reagents, and formation of weak chemical complexes. 

The synthesis involves the nickel-catalyzed coupling of the mono-Grignard reagent derived from 3-alkyl-2,5-diiodothiophene (82,83). Also in that year, transition-metal hahdes, ie, FeCl, MoCl, and RuCl, were used for the chemical oxidative polymerization of 3-substituted thiophenes (84). Substantial decreases in conductivity were noted when branched side chains were present in the polymer stmcture (85). 

The refined grade s fastest growing use is as a commercial extraction solvent and reaction medium. Other uses are as a solvent for radical-free copolymerization of maleic anhydride and an alkyl vinyl ether, and as a solvent for the polymerization of butadiene and isoprene usiag lithium alkyls as catalyst. Other laboratory appHcations include use as a solvent for Grignard reagents, and also for phase-transfer catalysts. 

Grignard reagents from, 5, 106 reactions, 5, 104 6, 274, 292 reactivity, 6, 292 synthesis, 6, 297 Thiazoles, imino-reactivity, 6, 250 Thiazoles, isopropenyl-radical polymerization, 6, 278 Thiazoles, mercapto-industrial uses, 6, 330 reactions, 5, 102 synthesis, 6, 298-299 tautomerism, 6, 247, 248, 269, 289 Thiazoles, methyl-... 

IV-substituted and B-substituted borazines are readily prepared by suitable choice of amine and borane starting materials or by subsequent reaction of other borazines with Grignard reagents, etc. Thermolysis of monocyclic borazines leads to polymeric materials and to polyborazine analogues of naphthalene, biphenyl, etc. ... 

Organotins. The organotin reagents have much lower nucleophilicity than that of the Grignard reagents, thus allowing the use of a variety of functionalized monomers for the polymerization. Aryl-alkenyl iodides, bromides and tosylates have been used as substrates. Palladium complexes are commonly employed as catalysts for the reaction. Because the catalysts can be destroyed... 

Soluble poly(l-butylperylene) (58) was prepared in very high yields by Anton and Mullen [70] who used the procedure of Taylor [71], which involves the oxidative coupling of bis-Grignard reagents with as-l,4-dichloro-2-butene as an oxidant. The products contain 4,9- and 4,10-perylenylene moieties, are fully soluble and possess average degrees of polymerization of ca. 22. 

When the temperature was slowly raised, no reaction was observed until 20° C, at which time polymerization occurred. In confirmatory experiments, 1-bromopentane reacted quantitatively with Mg in 1 min at -78° C. The resulting Grignard reagent did not react with subsequently added ... 

Promoted coupling of the Grignard reagent from 2,5-dibromoselenophene affords poly-2-5-selenienylene as shown in Eq. (43). Nickel(II) promoters gave the best results in terms of degree of polymerization and yields.155... 

In the 1952 paper mentioned above [3], Gilman reported on the formation of lithium dimethylcuprate from polymeric methylcopper and methyllithium. These so-called Gilman cuprates were later used for substitution reactions on both saturated [6] and unsaturated [7, 8, 9] substrates. The first example of a cuprate substitution on an allylic acetate (allylic ester) was reported in 1969 [8], while Schlosser reported the corresponding copper-catalyzed reaction between an allylic acetate and a Grignard reagent (Eq. 2) a few years later [10]. 

Braun et al. [258] used a combination of tert-butyllithium (t-BuLi) and tetramefhy-lethylenediamine to create initiator sites at the surface of carbon black for the LASIP of styrene. Schomaker et al. [259] first immobilized a methyl methacrylate derivative on colloidal silica and after activation by a Grignard reagent polymerized MMA. 

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