2-methylbut

E-MeCH=CHCH2Br 91 44 (Pent-3-enoic acid) 4 (2-Methylbut-3-enoic acid) 52 (Z-2-Methylbut-2-enoic acid)... 

Representative procedure for the gold-catalyzed intermolecular hydroalkoxylation of allenes. (4-(2-Methylbut-3-en-2-yloxy)butyl)benzen ... 

To a stirred solution of 3-methylbuta-1,2-diene (19.1 mg, 0.28 mmol) and 4-phenyl-l-butanol (0.43 mL, 2.8 mmol) in anhydrous DMF (0.28 mL) at 0 °C was added IPrAuCl (17.4 mg, 0.028 mmol) and AgOTf (7.2 mg, 0.028 mmol). This was left to stir under N2 atmosphere at 0 °C for 20 h. The reaction mixture was then flushed through two plugs of silica (Et20), washed with water and brine, and then dried over anhydrous MgS04. The product, (4-(2-methylbut-3-en-2-yloxy)butyl)benzene, was obtained by flash column chromatography (eluent 98 2 n-pentane Et20) as a clear colorless liquid (49.9 mg, 0.23 mmol, 82%). ... 

Indol-l-ylzinc chloride 3-Methylbut-2-enoyl chloride 70 [1]... 

Methylbut-2-enyl)- Diethyl formamidomalonate Toluene, NaOH 78 [17]... 

Bromo-3-[2-(t-butoxycarbonylamino)-2-(ethoxy-carbonyl)ethenyl]-l (4 methylphenylsulfonyl) 2-Methylbut-3-en-2-ol, Pd(PPh3)203, Ag2C03, EtjN 83 [3]... 

Thioethers (105) have also been reported as main products in the reaction between 2-lithium thiazolyl (103) and bis(3-methylbut-2-enyl)-disulhde (104) (Scheme 53) (268). 

Citral is prepared starting from isobutene and formaldehyde to yield the important C intermediate 3-methylbut-3-enol (29). Pd-cataly2ed isomeri2ation affords 3-methylbut-2-enol (30). The second C unit of citral is derived from oxidation of (30) to yield 3-methylbut-2-enal (31). Coupling of these two fragments produces the dienol ether (32) and this is followed by an elegant double Cope rearrangement (21) (Fig. 6). 

Useful selectivity between allyl and 3-methylbut-2-enyl (prenyl) ethers has been achieved. ... 

Polyolefins with branched side chains other than P4MP1 have been prepared Figure 11.14). Because of their increased cohesive energy, ability for the molecules to pack and the effect of increasing chain stiffness some of these polymers have very high melting points. For example, poly-(3-methylbut-l-ene) melts at about 240°C and poly-(4,4-dimethylpent-l-ene) is reported to have a melting point of between 300 C and 350°C. Certain cyclic side chains can also... 

Methylbut-2-enyl (Prenyl) Ester (CH3)2C=CHCH202CR Cleavage... 

Thus, 1,4-dibenzoyl- 1,3-butadiyne with diazomethane forms 3(5)-benzoylethy-nylpyrazole (yield 59%) (68LA124). In a similar way, the reaction of 2,7-dimethyl-octadiyne-2,7-diol with diazomethane leads to 4-[3-(l-hydroxy-l-methylethyl)-l//-pyrazol-4-yl]-2-methylbut-3-yn-2-ol in 64% yield (58CB1841) (Scheme 7). 

Tietze et al. investigated the Diels-Alder reaction between 44 and 2-methylbut-2-ene at the B3-LYP/6-31G level (Scheme 30) [98EJ02733]. 

In the next step, one of the borane-hydrogens is transferred to a sp -carbon center of the alkene and a carbon-boron bond is formed, via a four-membered cyclic transition state 6. A mono-alkyIborane R-BH2 molecule thus formed can react the same way with two other alkene molecules, to yield a trialkylborane R3B. In case of tri- and tctra-substituted alkenes—e.g. 2-methylbut-2-ene 7 and 2,3-dimethylbut-2-ene 9—which lead to sterically demanding alkyl-substituents at the boron center, borane will react with only two or even only one equivalent of alkene, to yield a alkylborane or mono alky Iborane respectively ... 

To a solution of sodium 3-methylbut-l-oxide [prepared from Na (0.04 g) and 3-methylbutan-l-ol (1.7 rnL) at 100 C], 3-phenoxyphthalonilrile (3, R = PhO 0.44 g, 2 mmol) was added. The mixture was refluxed for 2 h and then cooled. The precipitate formed was filtered, washed with 3-methylbutan-l-ol and ElOH until the filtrate was colorless, and treated on the filter with coned HC1. The hydrochloride obtained was dissolved in acetone and the solution was treated with dil NH4OH yield 0.16 g (36%). 

Treating naphthalene-2,3-dicarbonitrile with sodium 3-methylbut-l-oxide in 3-methylbutan-l-ol for five hours at reflux gives 2,3-naphthalocyanine 1, which, when stirred with methanol at room temperature, gives the metal-free 2,3-naphthalocyanine (2). 

Hydroxy-3-methylbut-l-ynyl)quinoxahne (113) gave 2-ethynylquinoxaline (114) by loss of acetone (dry NaOH, PhMe, reflux, 2 h 75%) several... 

A more recent paper by Rycroft and Cole (2001) described a study of Plagiochila rutilans Lindenb. From Bolivia, Brazil, and Costa Rica (all freshly collected) and Cuba and Ecuador (dried specimens). Material from Cuba had been described by Huneck et al. (1984) to contain, among other compounds, l-(3,4-dihydroxy-5-methoxyphenyl)-3-methylbut-2-ene. In the recent paper, Rycroft and Cole present evidence that the correct structure of the compound is l-(2,5-dihydroxy-3-methoxyphenyl)-3-methylbut-2-ene, which can also be called 2-methoxy-6-prenylhydroquinone. The corresponding quinone was also observed as a minor constituent. 

Huneck, S., Connolly, J. D., Harrison, L. J., Joseph, R. S. L, and Poes, T. 1984. l-(3, 4-Dihydroxy-5-methoxyphenyl)-3-methylbut-2-ene from the liverwort Plagiochila rutilans. Phytochemistry 23 2396-2397. 

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