Diols ethylene derivatives with

Hydrogen per oxide formic acid Diols from ethylene derivatives with exo-endo-rearrangement... 

Polyester and polyether diols are used with MDI in the manufacture of thermoplastic polyurethane elastomers (TPU). The polyester diols are obtained from adipic acid and diols, such as ethylene glycol, 1,4-butanediol, or 1,6-hexanediol. The preferred molecular weights are 1,000 to 2,000, and low acid numbers are essential to ensure optimal hydrolytic stabihty. Also, caprolactone-derived diols and polycarbonate diols are used. Polyether diols are... 

The first catalytic asymmetric [2+2] cycloaddition reaction was reported in 1989 by the use of the chiral titanium reagent prepared from the tartrate-derived chiral 1,4-diol 1 and TiCl2(0-z-Pr)2 [26]. Treatment of methyl ( )-4-oxo-4-(2-oxo-l,3-oxazolidin-3-yl)-2-butenoate (2a) and l,l-bis(methylthio)ethylene (3a) with a 10 mol % amount of the chiral titanium reagent in a mixed-solvent of toluene and petroleum ether (RE.) at 0 °C afforded the cyclobutane derivative 4a in 96% yield in nearly optically pure form (98% ee) (Scheme 1). In this section we... 

Okahara and coworkers prepared a number of Ai-alkylamino diols that were not symmetric. They first prepared the monochloride derivative of the oligoethylene glycol by reacting ethylene oxide with 2-chloroethanol in an acidic medium (Kuo et al., 1980). The oligomers were separated by distil-... 

Work by Nishikubo et al. [139] showed that the polymerization of divinyl ethers derived from aliphatic diols gave polymers with different structures, depending on whether cationic or free-radical initiators were used. Shown in equation (29) are the structures of the polymers obtained from polymerization of ethylene glycol divinyl ether using AIBN and iodine. 

The formation of the diol (167) from the reaction of di-t-butyl ketone with sodium in diethyl ether has been re-investigated, and a new mechanism (Scheme 93) proposed the involvement of ethylene, derived from diethyl... 

Lithium perchlorate/calcium carbonate Ring expansion of isocyclic diol monotosylates with preceding preferential formation of glycols from ethylene derivatives and preferential O-tosylation... 

Heating 1,4,5,6-tetra-O-benzyl-myo-inositol with ethylene carbonate and a trace of sodium bicarbonate affords the 2,3-cyclic carbonate derivative. The reaction fails where there is a trans-diol arrangement as with 1,2,3,6-tetra-O-benzyl-myo-inositol. ... 

Corey and Hase have found that 1,3-dithiolans and 1,3-dithians can be converted in good yields into dimethyl acetals, cyclic acetals, or thioacetals (or thioketals) upon reaction of the mono-5-methylated derivatives with methanol, ethylene glycol, and mercaptoethanol, respectively. These interchanges do not appear to involve the free carbonyl compound. The disulphonium salt prepared by the reaction of triethyloxonium tetrafluoroborate with 2-phenyl-l,3-dithiolan can be used to prepare benzylidene derivatives of 1,2-, 1,3-, and 1,4-diols (30— 80%) under basic conditions. This reaction appears to have considerable potential as a route to benzylidenated sugars. 

Diols that bear two hydroxyl groups m a 1 2 or 1 3 relationship to each other yield cyclic acetals on reaction with either aldehydes or ketones The five membered cyclic acetals derived from ethylene glycol (12 ethanediol) are the most commonly encoun tered examples Often the position of equilibrium is made more favorable by removing the water formed m the reaction by azeotropic distillation with benzene or toluene... 

Diol Components. Ethylene glycol (ethane 1,2-diol) is made from ethylene by direct air oxidation to ethylene oxide and ring opening with water to give 1,2-diol (40) (see Glycols). Butane-1,4-diol is stiU made by the Reppe process acetylene reacts with formaldehyde in the presence of catalyst to give 2-butyne-l,4-diol which is hydrogenated to butanediol (see Acetylene-DERIVED chemicals). The ethynylation step depends on a special cuprous... 

Macrocyclization of esters of allylglycine with diols has been successfully used to prepare derivatives of 2,7-diaminosuberic acid [861,864]. The latter are surrogates of cystine, and therefore of interest for the preparation of peptide mimetics. For unknown reasons protected allylglycine derivatives can not be directly dimerized by self metathesis [864]. However, catechol [864], ethylene glycol [861], and 1,2- or 1,3-di(hydroxymethyl)benzene derivatives [860] of allylglycine are suitable templates for the formal self metathesis of this amino acid via RCM. 

Both the (RR)- and (5S)-enantiomers of hydrobenzoin (Figure I4a) have been made to react (110, 117, 118) successfully in a (2 + 2) cyclization with ethylene glycol ditosylate in the presence of bases (e.g., NaOH in dioxane or NaH in MA -dimethylformamide) to give the enantiomeric tetiaphenyl-18-crown-6 derivatives (RRRR)-73 and (SSSS)-73. The corresponding optically pure tetra-anisyl, tetra-a-naphthyl, and tetra-/3-naphthyl-18-crown-6 derivatives 74, 75, and 76, respectively, have also been prepared in similar fashion (119). It should be noted that (RRRR)- and (,SSSS)-73 have also been obtained as a result of a base-promoted (1 + 1) cyclization (120) between the chiral extended diol and... 

If a diastereomeric mixture of (S,S)-2,5-dimethyl-3.4-hexanediol esters 2 and 3 reacts with methylmagnesium bromide, the result is kinetic resolution, as verified for R1 = Bn. The diastereomeric mixture was prepared from the racemic ethylene glycol a-chloro boronic ester via transesterification with chiral diol. The products isolated were (S,S)-2,5-dimethyl-3,4-hexanediol [(/ )-2-phcnyl-l-methylethyl]boronate, diastereomeric ratio >95 5 as indicated by the rotation of the (/ )- -phenyl-2-propanol derived by deboronation with hydrogen peroxide, and (S,S)-2,5-dimethyl-3.4-hexanediol methylboronate. Phenylacetaldehyde was identified by 1H NMR4. 

TABLE 3. Physical Properties of Inclusion Complexes of a- or 7-Cyclodextrins with Poly ethylene oxide-6-[(R)-3-hydroxybutyrate] diol-t>-ethylene oxide Derivatives... 

Treatment of MFA (1) with cyanogen bromide [6] opened ring G to yield the bromo derivative 3 [7]. Attempts to dehydrobrominate 3 in one step via a base-catalyzed elimination with DBU/CH3CN, KOH/MeOH, or terr-BuOK/DMSO were unsuccessful. However, the required methylene entity could be introduced by converting 3 first to a selenide, then oxidation with periodate, followed by thermolysis in benzene to provide compound 4. Hydrolysis of the cyano group with NaOH in ethylene glycol [8] produced 5 (50% yield). Osmium catalyzed oxidation of 5 in the presence of 4-methylmorpholine A-oxide (NMO) gave a diol, which was cleaved to an aldehyde upon treatment with periodate. Treatment of the aldehyde with sodium cyanoborohydride resulted in an intramolecular reductive animation to yield the desired product PHB (6). 

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