Alkoxy alcohol

This synthetic process is applicable to the preparation of other ketene acetal derivatives of /3-alkoxy alcohols. Examples include the ketene acetal derivatives of tetrahydrofurfuryl alcohol and l-methoxy-2-propanol.3 There are a number of advantages in its use, including a simple, time-saving procedure, readily available and inexpensive reagents, and good yields of ketene acetal obtained by a one-step method. 

Scheme 6.27 Typical P-alkoxy alcohols obtained from the highly regioselective alcoholysis of styrene oxides catalyzed by thiourea 9 and mandelic acid 20 in a cooperative organocatalytic system.

The addition of anilines to styrene oxide was reported to also proceed in the presence of 10mol% 37 affording the corresponding P-amino alcohols 1-5 in yields ranging from 75% to 92% (Scheme 6.37). Additionally, urea derivative 37 (20mol% loading) was found to catalyze the addition of aniline (2.0 equiv.) to ( )-stilbene oxide (92% yield 5.9 d 30°C), the addition of thiophenol (2.0 equiv.) to 2-methoxy styrene oxide (85% 20h rt), and the alcoholysis of 4-methoxy styrene oxide with benzyl alcohol (2.0 equiv.) affording the respective P-alkoxy alcohol (82% 20h rt). 

Preparation of alkoxy alcohol Acid-catalysed unsymmetrical propylene oxide gives 1-substituted alcohols, resulting from the nucleophilic attack on the most substituted carbon. For example, propylene oxide reacts with alcohol in the presence of acid to give 2-methoxy-l-propanol. 

Preparation of alkoxy alcohol Ethylene oxide is a symmetrical epoxide, which reacts with sodium methoxide to produce 2-methoxy-ethanol, after the hydrolytic work-up. 

Kuryla and Leis [125a] recently reported that ortho esters are readily produced by the slow addition of vinylidene chloride to a sodium j8-alkoxy-alcoholate, dissolved or suspended in a solvent. The reaction is exothermic and produces either the ketene acetal or the ortho ester derivative while sodium chloride precipitates (Eq. 38). 

Experiments with catalysts which are known to catalyze the alkylation reaction in the liquid phase (ref. 3), showed that the desired gas-phase reaction of substituted anilines with alkoxy-alcohols occurs, but with very low yield. Pd promoted copper chromite catalysts which are able to catalyze the alkylations of sterically hindered anilines with primary alkoxyalcohols (ref. 4, 5) showed only very low activity and selectivity when secondary alcohols were used. 

Although no mechanism is proposed for the dimerization of lactic acid in the FSOsH-SbFs solution, the process may very well involve the superelectrophile 147. Other oxonium-carbenium 1,3-dications have been suggested in superacid promoted pinacolone rearrangments of diprotonated aliphatic glycols and alkoxy alcohols (eqs 49-50).58... 

The 1,2-diX relationship presents a different series of opportunities in which we use the second functionality to make the right carbon atom electrophilic. The amino, thio- and alkoxy- alcohols 33 to 35 all fit the pattern 36 and can be disconnected to the usual heteroatom nucleophile and the synthon 37. 

In Alcohols When the acid-catalyzed opening of an epoxide takes place with an alcohol as the solvent, a molecule of alcohol acts as the nucleophile. This reaction produces an alkoxy alcohol with anti stereochemistry. This is an excellent method for making compounds with ether and alcohol functional groups on adjacent carbon atoms. For example, the acid-catalyzed opening of 1,2-epoxycyclopentane in a methanol solution gives fran.v-2-methoxycyciopcntanol. 

Epoxides open in acidic alcohol solutions to form 2-alkoxy alcohols. Step 1 Protonation of the epoxide to form a strong electrophile. 

Step 3 Deprotonation to give the product, a 2-alkoxy alcohol. 

Thus good yields of -alkoxy alcohols can be obtained, albeit as diastereomeric mixtures, but unfortunately hydroxymercurated alkenes under similar conditions do not lead to useful products. Despite this apparent limitation, alkoxymercuration-oxidative demercuration has been very effective in a number of systems described below, and there is no doubt it is a procedure worth consideration for hydroxy group introduction. 

Fair yields of alkoxy alcohols are obtained from a-alkoxy ketones and Grignard reagents. Methylmagnesium iodide and phenoxyacetone give plienoxy-l-butyl alcohol (88%). ... 

The reduction of a,p-unsaturated aldehydes and ketones by NaBH4 leads, in general, to substantial amounts of fully saturated alcohols. In alcoholic solvents, saturated -alkoxy alcohols can be formed via conjugate addition of the solvent. This latter process becomes the main reaction path when reduction is performed in 2-propanol in the presence of sodium isopropoxide. In base, a homoallylic alcohol can become the major product of borohydride reduction of an enone. Analysis of the influence of substrate structure on NaBH4 reduction has shown that increasing steric hindrance on the enone increases 1,2-attack. ... 

Special multicomponent catalysts were necessary for N-aUcylation of sterically hindered anilines with alkoxy alcohols [9]. Doping Cu-chromite with Pd accelerated the hydrogenation of the imine intermediate this was found to be the rate-limiting step for all the catalysts. Alkali cations (Na and Ba ) increased the activity whereas acidic centers (e. g. Cr " " and Al ) favored hydrogenolysis of the ether bond. For N-alkylation with secondary alkoxy alcohols a Pt/Si02 catalyst doped with Sn + and Ca ions afforded the best performance. Yields of mono-alkylated anilines varied in the range 22-93 % depending on the steric hindrance in the reactants. 

Bis[dicarbonylchlororhodium(I)] and bis[(l,5-cyclooctadiene)chlororhodium(I)], Epoxide opening. The monoepoxide of a diene is regioselectively attacked by nucleophile (ArNHR, ROH) at the allylic position using [Rh(CO)2Cl]2 as catalyst, affording anil-1,2-amino alcohols and alkoxy alcohols. The results are apparently complementary to those obtained from the Pd-catalyzed process. 

Anodic oxidation of ot-amino- or a-alkoxy-alcohols leads to the formation of ketones. Particularly noteworthy is the preparation of an o>-oxoketal on oxidation of a 2-alkoxycycloaIkanol (Scheme 27). ... 

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