Diols from reactions with

One of the first attempts to produce polyurethane was from the reaction of an intermediate polyol of 1,3- and l,4-bis(hydroxyhexa uoroisopropyl)benzene m- and -12F-diols) by reaction with epichlorohydrin. This polyol was subsequentiy allowed to react with a commercial triisocyanate, resulting in a tough, cross-linked polyurethane (129,135,139). ASTM and military specification tests on these polyurethanes for weather resistance, corrosion prevention, bUster resistance, and ease of cleaning showed them to compare quite favorably with standard resin formulations. 

Since hydrogen peroxide, like alkyl hydroperoxides, can be alkylated by alkyl bromide plus silver trifluoroacetate (Eq. 19, R = H),35) an attractive variation of the silver-salt-induced dioxabicyclization uses cis- 1,3-dibromocycloalkane 43 as starting material. Thus Porter and Gilmore obtained 2,3-dioxabicyclo[2.2.1]heptane 9 in 30-40% yield from c s-l,3-dibromocyclopentane, which was itself obtained from the corresponding c/s-diol by reaction with triphenylphosphine dibromide (Eq. 31 R = R = H)36). 

The 1,2-cyclic sulfites are readily obtained from anomeric mixtures of 1,2-diols by reaction with sulfinyl diimidazolide as mixtures of exo- and endo-isomers at sulfur (Scheme 4.34) [312-314],... 

Using HF-SbF5, Yoneda et al.405 have obtained dicarboxylic acids from diols by reaction with CO under mild conditions. Some cyclization products were also obtained. Scheme 5.40 was suggested for the reaction. 

Reaction of thiochroman-3,4-diones with NaBH4 affords a mixture of the as- and trans- 3,4-diols and two keto alcohols result from reaction with MeMgl. Attempts to separate the latter mixture by preferential dehydration of the thiochroman-4-ol gave unchanged 3-hydroxythiochromanA-one, but no 4-methylenethiochroman-3-one was detected. Instead, a spiro-linked adduct arising from a hetero Diels-Alder cycloaddition between two molecules of the expected dehydration product was isolated (Scheme 102) <1994T7865>. 

The formal tin counterpart of the dioxolanes formed from vicinal diols by reaction with ketones are stannylenes, formed by reaction with dialkyltin oxides. The commonest reagent is dibutyltin oxide, Bu2SnO, which converts diols to stannylenes when refluxed in an aprotic solvent such as benzene, with continuous distillation out of the water generated. The partly ionic nature of... 

Z)-2,4-Diiodo-2-butenol An apparently valuable aUyUc alcohol is obtained in one step from 2-butyne-l,4-diol by reaction with Me3SiCl-NaI. 

Miscellaneous.- A simple method to resolve racemic l,l -binaphthalene-2,2 -diol involves reaction with menthyl phosphorodichloridite (139) and separation of the diastereomeric phosphites by crystallisation from ether. The new cyclic chlorodiaminophosphine (140), prepared in and two new cyclic triaminophosphines (141) have been used to determine the enantiomeric purity of chiral alcohols, thiols, and amines by means of Ip n.m.r. New optically pure phosphites used for Rh catalysed asymmetric hydroformylation reactions are (142), two diastereomers of (143), and (144) the diphosphinite (145) was similarly employed. Some new cyclic aminophosphines (146) were prepared for use as ligands in asymmetric Pd catalysed allylic substitution reactions. 

The (S)-lactone acid 1, obtained from L-glutamic acid by nitrous acid deamination, was converted to the acid chloride, then treated with excess diazomethane followed by hydrogen iodide to yield the keto-lactone 2. Amidation occurred quantitatively to give the partially racemized amide 3, which was purified by repeated recrystallizations. The vicinal diol resulting from reaction with excess methylmagnesium iodide was protected as the acetonide 4. An isomeric mixture of olefins (Z , 26 74) was obtained from the subsequent Wittig reaction. Reduction followed by separation on silver nitrate coated silica gel gave the (Z)-and ( )-alcohols in 20% (6) and 61% (5) yield, respectively. Conversion of the (S)-( )-alcohol (5) to the chloride then afforded the thioether (7) on reaction with sodium phenylsulfide. The thio ether anion was formed by treatment with n-butyllithium. Alkylation with the allylic chloride" (8), followed by removal of sulfur, then yielded the diene 9, which was converted in several steps to (/ ) (-t-)-10,11 -epoxy famesol. 

Enantiopure aziridines can also be obtained from chiral 1,2-diols. These are converted into cyclic sulfates 68, " or cyclic sulfites 69. These compounds are also cleaved by reaction with lithium azide or sodium azide to azidoalcohols which can then be converted into aziridines as above. The sulfates 68 can be prepared in one pot and in high yield from the diols by reaction with thionyl chloride followed by oxidation with sodium periodate and ruthenium trichloride. Sulfites 69 are available from diols simply by reaction with thionyl chloride. An example of the use of a cyclic sulfate is the preparation of the aziridine 71 in good yield and with high ee from the chiral sulfate 70 (Scheme... 

Cyclic carbonate esters are easily prepared from 1,2- and 1,3-diols, by reaction with N,N -carbonyldiimidazole or by transesterification with diethyl carbonate. 

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... 

The 1,4-isomer has been similarly generated from terephthalonitdle [623-26-7] (56) using a mixed Pd/Ru catalyst and ammonia plus solvent at 125 °C and 10 MPa (100 atm). It is also potentially derived (57) from terephthaUc acid [100-21-0] by amination of 1,4-cyclohexanedimethanol (30) [105-08-8], Endocyclization, however, competes favorably and results in formation of the secondary amine (31) 3-a2abicyclo[3.2.2]nonane [283-24-9] upon diol reaction with ammonia over dehydration and dehydrogenation catalysts (58) ... 

The initial step is the protonation of the aldehyde—e.g. formaldehyde—at the carbonyl oxygen. The hydroxycarbenium ion 6 is thus formed as reactive species, which reacts as electrophile with the carbon-carbon double bond of the olefinic substrate by formation of a carbenium ion species 7. A subsequent loss of a proton from 7 leads to formation of an allylic alcohol 4, while reaction with water, followed by loss of a proton, leads to formation of a 1,3-diol 3 " ... 

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