Butylmagnesium bromide 3- methyl

Butylmagnesium bromide-Methyl-aluminum bis(2,6-di-/-butyl-4-methyl-phenoxide), 203... 

The rate of the reaction decreases with increasing number of substituents in the acetylenic halide, and it is higher with acetylenic bromides than with the corresponding chlorides. Methyl magnesium iodide gives equal amounts of 1,1- and 1,3--substitution products, whereas tert.-butylmagnesium bromide does not react. However, for some tert.-butyl substituted allenes there exists an attractive com-... 

The ratio of 1,2 and 1,4-addition products is approximately 1 1. However, addition of cuprous chloride to the methyl Grignard reagent leads to exclusive 1,4-addition in yields greater than 90%. ° With isopropyl- and /-butylmagnesium bromide, only 1,4-addition products are isolated even in the absence of cuprous chloride. ... 

Metalation ofa-sulfinyl dimethylhydrazones with terf-butylmagnesium bromide, butyllithium or lithium diisopropylamide, and reaction of the generated azaenolates with aldehydes, provides aldol adducts (e.g., 6) as mixtures of diastereomers. Reductive desulfurization leads to fi-hydroxy dimethylhydrazones (e.g., 7) which are cleaved to the desired /(-hydroxy ketones in 25% overall yield10 u. The enantiomeric excesses are about 50%, except for (- )-3-hydroxy-4-methyl-1-phenyl-1-pentanone (8) which was obtained in 88% ee. 

Figure 1. Isotactic, heterotactic, and syndiotactic triad frequencies (i, h, and s) in poly(methyl methacrylate) polymerized and initiated at 225 by t-butylmagnesium bromide fleft), t-butylmagnesium chloride fright,), and di-t-butylmagnesium (top) with initial mole fraction of monomer a = 0.10.

Butylmagnesium bromide-Vanadi-um(III) chloride, 219 Chlorobis(cyclopentadienyl)hydrido-zirconium(IV)-Magnesium, 351 Ethylmagnesium bromide, 203, 221 Ethylmagnesium bromide-Methyl-aluminum bis(2,4,6-tri-f-butyl-phenoxide), 203... 

One of the first detailed studies on these systems was that of Beaman (26), who showed that methacrylonitrile polymerizes by an anionic chain mechanism when treated with various bases, including Na in liquid ammonia at —75° C. He noted also that low molecular weight polymers are obtained from reaction of acrylonitrile with butylmagnesium bromide. Foster (56) extended the liquid ammonia method to copolymerization studies in which acrylonitrile was combined with styrene, with methyl methacrylate and with vinyl butyl sulfone. Satisfactory data were obtained only with the sulfone, in which case there was some tendency for alternation. 

The distribution of S, 2, SN2 products (146,147) for the reaction between trans-oL-methyl-y-phenyl allyl pivaloate 145 and n-butylmagnesium bromide in Et20 [see Eq. (48], was studied as a function of the nature of the organocopper species [61] (Table 11). 

Usually, all the initiator used cannot be accounted for if each macromolecule or oligomer is assumed to contain only one initiator fragment. By polymerizing methyl methacrylate-d8 with nondeuterated n-butylmagnesium bromide, the fate of the initiator molecules could be studied in detail by H-NMR [22,38-44]. In toluene at —78 C, n-butylmagnesium bromide attacks equally the C=C [Eq. (2)]... 

Hatada, K. Ute, K. Yamamoto, M. Nishimura, T. Kashiyama, M. On-line GPC/NMR analyses of block and random copolymers of methyl and butyl methacrylates prepared with tert-butylmagnesium bromide. Polym. Bull. 1989,21, 489 95. 

Scheme 4 Preparation of the aglycone of OSW-1 (2). (a) PhsPEtBr, rm-BuOK, 78% TBDPSCl, 100%. (b) (CH2OX, Bp30Et2, 75%. (c) Dess-Martin periodinane, 86% 3-methyl-butylmagnesium bromide, 96%. (d) PDC, 83% HOCHjCHjOH, 96%. (e) TBAF, 95% TBSCl, 96%. (f) OSO4, 41%. (g) ClCOCOCl, DMSO, 78% NaBH CeCE, 93%.

On addition of methyllithium in tetrahydrofuran/diethyl ether, pyrido[3,4-r/]pyridazine gives a 1 1 mixture of the two isomeric 1,2- and 4,3-addition compounds, i.e. 1-methyl-1,2-dihydropy-rido[3,4-r/]pyridazine (10) and 4-methyl-3,4-dihydropyrido[3,4-<7]pyridazine (11), which are readily oxidized by air to yield the fully aromatic systems (see Section 7.2.1.5.1.3).6 129 If the pyridazine ring is deactivated by amino substituents as in l,4-dimorpholino-7-phenylpyri-do[3,4-r/ pyridazine or its 5-methyl derivative, addition of organometallics such as benzyllithi-um, benzylmagnesium chloride or rcrt-butylmagnesium bromide occurs at the pyridine ring and yields 5-alkyl-5-methyl-l,4-dimorpholino-7-phenyl-5,6-dihydropyrido[3,4-d]pyridazines 12.119... 

The reaction thus affords primary alcohols with the chain lengthened by two carbon atoms for example, hexyl alcohol has been prepared in 60% yield from butylmagnesium bromide and oxirane.198 Malinovski and Konevichev199 treated 2-isopropyloxirane with ethylmagnesium bromide and obtained 2-methyl-3-hexanol ... 

In the literatures we can find out a number of data which indicate the formation of heterotactic polymers, although the authors have not commented about it. These Include poly(methyl methacrylate) and poly(ethyl methacrylate) obtained by octyl-potassium, biphenylpotassium, fluorenylpotassium (Table 5), benzylcal-dum or potassium alkoxide in polar solvent, and poly(phenyl methacrylate) prepared by n-, iso- and sec-butylmagnesium bromide in toluene at low temperature (Table S). These clearly indicate that not only the size of the substituent of monomer but also the nature of the counter cation or the pdymerization medium is important factor for the formation of heterotactic polymer. 

---