Cis-2-Buten-l,4‘diol

ABA triblock copolymers, where A was PBd and B either PS or PMMA were prepared by the combination of ROMP and ATRP techniques [122], The PBd middle blocks were obtained through the ROMP of cyclooctadi-ene in the presence of l,4-chloro-2-butene or cis-2-butene-l,4-diol bis(2-bromo)propionate using a Ru complex as the catalyst. The end allyl chloride or 2-bromopropionyl ester groups were subsequently used for the ATRP of either styrene or MMA using CuX/bpy (X = Cl or Br) as the catalytic system (Scheme 50). Quantitative yields but rather broad molecular weight distributions (Mw/Mn higher than 1.4) were obtained. 

We have observed that diol 3, cis-2-butene-l,4-diol, and cis-1,2-bis(hydroxymethyl)cyclohexane react smoothly with TPP-CClq to afford 4 (78%), 2,5-dihydrofuran (65%), and cis-8-oxabicyclo[4.3.0]-nonane 84%). Reaction of diol 5 with TPP-CCli in CH3 CN gives 52% of 5-chloropentanol, 6 (11%), and 1,5-dichloropentane (25%) while diol 7 affords 6-chlorohexanol (48%) and 1,6-dichlorohexane (39%). Comparisons of the ether chlorohydrin dichloride product distributions arising from these simple diols reveal a trend for efficiency of chain closure to 3 - 7 membered rings where the formation of cyclic ethers appear to decrease in order of the following ring size 3-5>6>4-7. 

Starting from commercial, cis-2-buten-l,4-diol, the monotrichloroacetimidate was obtained as a colorless liquid (60%, b.p. 88°-102°C/0.2 mm Hg) by treatment with trichloroacetonitrile (1 equivalent) in tetrahydrofuran at -23°C in the presence of catalytic amount of sodium. Monotrichloroacetimidate upon refluxing in tert-butyl benzene for about 1 hour underwent, smoothly,... 

The aminocyclitol moiety was synthesized in a stereocontrolled manner from cis-2-butene-l,4-diol (Scheme 40)112 by conversion into epoxide 321 via Sharpless asymmetric epoxidation in 88% yield.111 Oxidation of 321 with IBX, followed by a Wittig reaction with methyl-triphenylphosphonium bromide and KHMDS, produced alkene 322. Dihydroxylation of the double bond of 322 with OSO4 gave the diol 323, which underwent protection of the primary hydroxyl group as the TBDMS ether to furnish 324. The secondary alcohol of 324 was oxidized with Dess-Martin periodinane to... 

Arylation of the 4,7-dihydro-l,3-dioxepin system 68 (easily derived from cis-2-butene-l,4-diol), once again using the triflate, was reported by Shibasaki et al. in 1994 [57]. The reaction is significant in that the resulting enol ethers are easily converted (by hydrolysis and then oxidation of the intermediate lactol) to chiral P-aryl-y-butyrolactones 70, which are themselves useful synthetic intermediates (Scheme 18) [58]. Also noteworthy is the important role played by added molecular sieves (MS), which enhance both chemical yield and ee. This was the first time that such an effect had been noted for the AHR. 

Monomers. MA was purified by multiple recrystallizations and/ or subliniation. The monomer N-phenylmaleimide was prepared by a known procedure (13) and recrystallized several times to obtain high purity. Treatment of cis-2-butene-l,4-diol with a two-fold molar excess of acetic anhydride for 6 hr. at 100°C was the method of choice to prepare cis-2-butene-l,4-diol diacetate, bp 55-60°C/ 0.1mm [lit. 120-l°C/18mm (28)1). Dimethyl maleate and di-ti-butyl fumarate were dried over sodium sulfate and distilled. The cis-2-butene-l,4-diol starting material contained ca. 8% trans isomer, as shown by NMR. 

As background information, an attempt was made to copolymerize cis-2-butene-l,4-diol diacetate with MA. Heating equimolar mixtures of the two monomers with AIBN (2 wt%) for 15 hr. at 75°C produced only a very low yield (<10%) of polymeric material. Using the same conditions, equimolar mixtures of IA-di-t-butyl fumarate and IA-dimethyl maleate gave only a trace of copolymer. Yokayama and Hall (10) also repored that diethyl maleate and diethyl fumarate undergo free-radical copolymerization with IA to give very low yields of non-equimolar copolymer. 

BUTENEDIOL or 2-BUTENE-l,4-DIOL or cis-2-BUTENE-l,4-DIOL (110-64-5) C4H8O2 Combustible liquid (flash point 263°F/128°C oc). Contact with strong oxidizers may cause fire and explosions. Reacts violently with oxidizers, aliphatic amines, alkalis, ammonium persulfate, boranes, bromine dioxide, isocyanates, nitric acid, perchlorates, permanganates, peroxides and hydroperoxides, sodium peroxide, sulfuric acid, uranium fluoride. 

Selective hydrogenation. Butynediol can be selectively hydrogenated to cis-2-butene-l,4-diol in CF3CH2OH at -20° or in CgHg—CF3CH2OH at 0° with this catalyst. The product distribution is 94% of the enediol and 4% of the butanediol. The same selective hydrogenation can be realized with IrQ(CO)-(P(C6Hs)3]2 as catalyst in toluene-trifluoroethanol at 60° under weak UV irradiation. ... 

Butancdiol Butane-2,3-diol Butane-1,3-diol cis-2-butene-l,4-diol... 

Plqrsical Properties of Technical Cis-2-Butene-l,4-Diol Boiling point range... 

Synthesis of dienyl chloride 2.349, the dithiane coupling partner for dithiane aldehyde 2.338, was accomplished in five steps from commercially available cis-2-butene-l,4-diol (Scheme 2.72). To this end, monosilylation of 2.344 as the TBS ether and this allyl alcohol was then oxidized with accompanying Zto E isomerization by PCC [122] to afford the enal 2.346 in 73 % yield. a,]S-unsaturated ester 2.347 was accessed by the Still—Gennari modification [219] of the Homer-Wads worth-Emmons olefination in good yield and selectivity (92 %, Z/E — 16 1). Reduction of the resulting ester 2.347 to produce allyl alcohol 2.348, in turn was chlorinated by treatment with LiCl and methanesulfonyl chloride to furnish the requisite dienyl chloride 2.349. 

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