Butadiene l,4-diol

In contrast, synthesis of 3,4-diphosphorylthiophenes requires more elaboration because of low reactivity of 3,4-positions of thiophene and unavailability of 3,4-dihalo or dimetallated thiophenes. Minami et al. synthesized 3,4-diphosphoryl thiophenes 16 as shown in Scheme 24 [46], Bis(phosphoryl)butadiene 17 was synthesized from 2-butyne-l,4-diol. Double addition of sodium sulfide to 17 gave tetrahydrothiophene 18. Oxidation of 18 to the corresponding sulfoxide 19 followed by dehydration gave dihydrothiophene 20. Final oxidation of 20 afforded 3,4-diphosphorylthiophene 16. 3,4-Diphosphorylthiophene derivative 21 was also synthesized by Pd catalyzed phosphorylation of 2,5-disubstituted-3,4-dihalothiophene and converted to diphosphine ligand for Rh catalysts for asymmetric hydrogenation (Scheme 25) [47],... 

Kolbe oxidation of carboxylate ions to radicals with loss of carbon dioxide (p. 312). The latter process gives highest yields of dimeric product at a platinum anode and only monomeric products from oxidation of the radical centre at a carbon anode. Oxidation of butadiene in methanol containing benzoic acid, at a smooth platinum anode, gives 45 % of the but-3-ene-l,4-diol diester [45]. 

REPPE PROCESS. Any of several processes involving reaction of acetylene (1) with formaldehyde to produce 2-butync-l,4-diol which can be converted to butadiene (2) with formaldehyde under different conditions to produce propargyl alcohol and, form this, allyl alcohol (3) with hydrogen cyanide to yield acrylonitrile (4) with alcohols to give vinyl ethers (5) with amines or phenols to give vinyl derivatives (6) with carbon monoxide and alcohols to give esters of acrylic acid (7) by polymerization to produce cyclooctatetraene and (8) with phenols to make resins. The use of catalysis, pressures up to 30 atm, and special techniques to avoid or contain explosions are important factors in these processes. 

Forthe Cs-aldehyde moiety, there are several access routes available. A comparatively simple option is the hydroformylation of l,2-diacetoxybut-3-ene, which is obtainable from but-2-ene-l,4-diol by esterification with acetic anhydride and a copper-catalysed rearrangement. Critical for this synthetic route is to control the regioselectivity of the hydroformylation. A recently developed process to prepare vinyloxirane from butadiene over a silver catalyst opens up a second attractive approach. [56, 57]... 

We preferred to find another route which avoided the monovinyl-acetylene required to make 4-chloro-l,2-butadiene ( ), and have devised a route based on 2-butyne-l,4-diol ... 

Dichloro-1,3-butadiene, CH2=CC1-CC1=CH2, serves as a monomer for special types of poly(chloroprene). It is produced either by reacting butyne-l,4-diol with... 

Buta-1,3-diene (10.101, Fig. 10.24) is a gaseous chemical used heavily in the rubber and plastics industry, the presence of which in the atmosphere is also a concern. Butadiene is suspected of increasing the risks of hematopoietic cancers, and it is classified as a probable human carcinogen. Butadiene must undergo metabolic activation to become toxic the metabolites butadiene monoepoxide (10.102, a chiral compound) and diepoxybutane (10.103, which exists in two enantiomeric and one meso-form) react with nucleic acids and glutathione [160 - 163], as does a further metabolite, 3,4-epoxybutane-l,2-diol (10.105). Interestingly, butadiene monoepoxide is at least tenfold more reactive than diepoxybutane toward nucleic acids or H20. Conjugation between the C=C bond and the oxirane may account for this enhanced reactivity. 

Both the mono- and diepoxides of butadiene are substrates for epoxide hydrolase [163], In rat liver microsomes, (R)- and (S)-butadiene monoepoxides were hydrolyzed to but-3-ene-l,2-diol (10.104, Fig. 10.24) with complete retention of configuration at C(2), indicating attack at C(l) [164], In mouse liver microsomes, in contrast, 15 - 25% inversion of configuration was observed, suggesting partial attack at C(2). Preliminary results indicate that human liver microsomes are more efficient than mouse or rat liver microsomes in hydrolyzing butadiene monoepoxide [165]. The hydrolysis of diepoxybutane (10.103) yields 3,4-epoxybutan-l,2-diol (10.105), which can be further hydrated to erytritol (10.106) [163]. 

A somewhat similar hydrogenation problem arose in a different approach to 1,4-butanediol and tetrahydrofuran.345 In the process developed by Mitsubishi, 1,3-butadiene first undergoes Pd-catalyzed diacetoxylation to yield 1,4-diacetoxy-2-butene. To avoid the further transformation of the diol as in the abovementioned process, l,4-diacetoxy-2-butene is directly hydrogenated in the liquid phase (60°C, 50 atm) on traditional hydrogenation catalysts to produce 1,4-diacetoxybutane in 98% yield, which is then hydrolyzed to 1,4-butanediol. 

Reaction of RCHO with 1,3-diene monoepoxides.4 The monoepoxides of butadiene or of isoprene after treatment with CrCl2 and 1A1 (2 l) react with aldehydes to form cis-l,3-diols with a quaternary center at C2. 

Lai J, Bigot S, Sauthier M, Molinier V, Suisse I, Castanet Y, Aubry J-M, Mortreux A (2011) Telomerisation of 1,3-butadiene with l,4 3,6-dianhydrohexitols an atom-economic and selective synthesis of amphiphilic monoethers from agro-based diols. ChemSusChem 4 1104-1111... 

A. 2,3-Bls(phenylsulflnyl)-1,3-butadiene. In a 2-L, three-necked, round-bottomed flask equipped with a mechanical stirrer, 25-mL dropping funnel, and a nitrogen inlet, are placed 7.75 g (0.09 mol) of 2-butyne-1,4-diol (Note 1), 37.6 ml. (0.27 mol) of triethylamine, and 700 mL of dichloromethane. After the diol is completely dissolved, the mixture is cooled to -78°C. To this solution is added 26.0 g (0.18 mol) of phenylsulfenyl chloride (Note 2) over a 30-min interval. The mixture is gradually warmed to room temperature and stirred for an additional 12 hr. The solution is then washed with 100 mL each of water, saturated ammonium chloride solution, saturated sodium bicarbonate solution, and brine, and dried over sodium sulfate. After filtration and concentration, the residue is recrystallized from methanol-ether (1 1) to give 20.1 g (74%) of 2,3-bis(phenylsulfinyl)-1,3-butadiene as a 1.1 1 mixture of diastereomers (Note 3). 

Butadiene has been converted into poly-l,4-(cis-butadiene) in greater than 98.3% by Ziegler-Natta catalysis comprising neodymium versatate, diethyl aluminum chloride, diisobutylaluminum hydride, and triisobutyMuminum. The polymer was then converted into a polybutadiene-polyurethane copolymer by reacting with a diisocyanate and diol. This copolymer exhibited low cold flow and high affinity for silica or carbon black, excellent elasticity, and abrasion resistance. 

Acid-catalyzed hydrolysis of isobutylene oxide (8) is >750 times faster than that of ethylene oxide (6), and > 99% of the glycol product is from addition of solvent at the tertiary carbon.23 These results are consistent with a mechanism in which there is significant positive charge on the tertiary carbon at the transition state, as discussed in the previous section. Butadiene monoepoxide (10) is slightly less reactive than isobutylene oxide,36 and its acid-catalyzed hydrolysis can potentially proceed via a resonance-stabilized allyl cation (Scheme 6). However, the acid-catalyzed hydrolysis of 10 yields 96% of 3-buten-l,2-diol (15) and only 4% of 2-butene-1,4-diol (16),36 and the acid-catalyzed methanolysis of 10 is reported to yield only 2-methoxy-3-buten-l-ol.37 An A-2 mechanism proceeding via transition state 17 may account for the observation that 1,2-diol 15 is the predominant product from acid-catalyzed hydrolysis of 10. The minor yield of the 1,4-diol 16 may be formed from reaction of... 

The most significant application of the C5-unit 73 (Scheme 7) is in the BASF process for the production of vitamin A [22]. Industrial syntheses of 73 [23] proceed via but-l-ene-3,4-diol diacetate (74) by acetylation and copper-catalysed rearrangement of 75. A new route is emerging via the vinyloxirane 76, which has recently become accessible via silver-catalysed gas-phase oxidation [24]. The diacetate 74 is formed as a byproduct in the oxidative acetoxylation of butadiene (14), which is performed on an industrial scale to produce butane-1,4-diol (77) [25]. 

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