Stryrene derivatives

In the case of the benzyl-substituted pentenoic add 240, bromination takes a different course to the case in Reaction scheme 164. Here, the bromine attacks the actually less favoured neopentyl-position to give the more stable stryrene derivative 241 (Reaction scheme 165). 

The Suzuki reaction was described in the presence of various [Pd(7 -allyl)Cl]2 (l)/ligand systems as well. The efficiency of the tetraphosphine ligand Tedicyp was demonstrated for various Suzuki couplings, and more recently for the reaction of alkenyl-boronic acids with arylbromides. 7i The preparation of various stryrene derivatives (eq 81) has been performed in the presence of vinylboronic acid and substituted alkenyl boronic acids. The catalyst system was tolerant of electronic variation in the aryl-bromide component. Tum-over numbers of 3100-8600 could be achieved for activated substrates such as 4-bromoacetophenone. The coupling of alkyl tosylates was described either in the presence of Pd(OAc)2 or dimer (1) as precursor. 7 a fiber-supported catalyst prepared from 1 was found to be efficient for Suzuki coupling between activated aryl bromides and phenylboronic acid. 

The compatibilizer improves the mechanical properties of PE/starch, and addition of a plasticizer is actually detrimental to the finished products. Although PE is used here to demonstrate the results of this invention, results are practically the same with other combinations of polymer and compatibilizer as disclosed therein. Incorporation of compatibiHzer is easily accomplished by mechanical blending of the polymer, starch, and compatibilizer prior to extrusion. Typically, the compatibilizer is composed of the same polymer as the primary polymer itself. The polymer component of the compatibilizer may be selected from the group consisting of polyethylene, polypropylene, polystyrene, polybutylene, poly(styrene-ethyl-ene-butylene-stryrene), poly(ethylene terephthalate), polyvinyl fluoride, polyvinyl chloride, or derivatives thereof [6]. 

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