Lithium alcoholate

Lithium alcohol sulfates are used in carpet-cleaning formulations due to their special foaming characteristics. 

Capillary tube isotachophoresis using a potential gradient detector is another technique that has been applied to the analysis of alcohol sulfates, such as sodium and lithium alcohol sulfates [303]. The leading electrolyte solution is a mixture of methyl cyanate and aqueous histidine buffer containing calcium chloride. The terminating electrolyte solution is an aqueous solution of sodium octanoate. 

This isomerization was used in the heteroconjugate addition to the acyclic system. Therefore, the substituted olefin 72, in which the double bond is conjugated with both sulfone and silicon atoms, undergoes a diastereoselective addition of CHsLi. The resulting lithium alcoholate is quantitatively converted into the silyl ether dianion 73 and the addition of deuterium oxide afforded the functionalized product 74 in excellent yield (equation 16. 

In order to avoid polymerization and to achieve better stereocontrol by quasi-intramolecular addition, a carbanion-stabilizing group and a complexing substituent for capturing alkyllithium/(—)-sparteine in the substrate are useful. This carbolithiation protocol was realized with great success by Marek, Normant and coworkers (equation 125) Addition of n-BuLi/(—)-sparteine (11) onto the lithium alcoholate derived from ( )-cinnamyl alcohol (457) in cumene at 0°C afforded the addition product with 82% yield and 80% ee. 

The moderate yield (between 40 and 55% in the various experiments) can in part be explained by the fast cyclizarion of Z-HCsCCH=CH20Na to 2-methylfuran. With lithium acetylide, a mixture of the E- and Z-isomer is obtained Apparently cyclization of the Z-lithium-alcoholate proceeds less easily [61]. 

Synthesis of the polymer-bound allyl sulfoximine 60 was accomplished by the addition-elimination-isomerization route starting from the enantiomerically pure polymer-bound N-methyl-S-phenylsulfoximine 59, which was prepared as previously described from Merrifield resin and sulfoximine 12 with a loading of 84% (Scheme 1.3.23) [42]. The successive treatment of resin 59 with n-BuLi in THF and with isovaleraldehyde furnished the corresponding polymer-bound lithium alcoholate, which upon reaction with ClC02Me and DBU afforded the corresponding polymer-bound vinylic sulfoximine (not shown in Scheme 1.3.23), the isomerization of which with DBU in MeCN afforded sulfoximine 60. 

The addition of substituted allylic zinc reagents to aldehydes is usually unselective" . Furthermore, the direct zinc insertion to substituted allylic halides is complicated by radical homocoupling reactions. Both of these problems are solved by the fragmentation of homoallylic alcohols. Thus, the ketone 166 reacts with BuLi providing a lithium alcoholate which, after the addition of ZnCl2 and an aldehyde, provides the expected addition product... 

In view of the mechanism suggested above for the ethanol-sodium reaction, it seems likely that reduction of aromatic compounds by solutions of alcohols and alkali metals in liquid ammonia proceeds by a general mechanism involving a steady-state concentration of ammonium ion. Krapcho and Bothner-By (29) observed that the reduction of benzene and several substituted benzenes in lithium-alcohol-ammonia solutions,... 

Acute endogenous depression is not generally considered to be an indication for treatment with lithium. Alcohol and substance abuse have a high association with bipolar illness. However, recurrent endogenous depressions with a cyclic pattern are controlled by either lithium or imipramine, both of which are superior to a placebo. 

English investigators reported [60] the synthesis of the title alcohol from epichlorohydrine and sodium acetylide in liquid ammonia. The synthesis is easily performable on a large scale and gives a useful intermediate. The relatively low yield is explained by the occurrence of a number of other processes, the principal one of which is probably the base-catalysed cyclization of Z-HC=CCH=CHCH2ONa to 2-methylfuran, which can be swept along with the ammonia vapour. When the synthesis is carried out with lithium acetylide, a mixture of comparable amounts of - and Z-pentenynol is obtained in a higher yield [61]. Apparently, the Z-lithium alcoholate cyclises less readily. 

A very recent paper by Saegusa, 7) describes a method of synthesizing polyoxyethylene macromonomers bearing a polymerizable heterocycle at the chain end. Here again the method involves initiation of the oxirane polymerization by means of an alcoholate (derived from 2-p-hydroxyphenyl)-oxazoline). As metalation agent butyllithium, was used since lithium alcoholates are not very reactive towards oxirane. Indeed, the macromonomers obtained exhibit very low degrees of polymerization. Deactivation was performed with methyl iodide ... 

Mono- and bis(ferrocenylethoxy) derivatives (153, 154) and a mono(ferro-cenylisoproxy) derivative (155) have been prepared by the reaction of (NPCl2)3 and the appropriate lithium alcoholates. Introduction of a second ferro-... 

Study of the effect of small amounts of iron salts on the reaction of metals with alcohols in liquid ammonia showed that 0.5 ppm. of iron increases the rate of reaction of lithium by a factor of 2 and increases the rate of reaction of sodium by a factor of 50. High yields were then achieved in Birch reductions conducted with sodium and f-butanol in iron-free ammonia. Evidently lithium had seemed superior to sodium merely because the lithium-alcohol reaction is catalyzed by iron much less strongly than the sodium-alcohol reaction is catalyzed. Actually sodium usually is as effective as lithium and in some cases definitely superior. Only in the case of 5-methoxytetralin did lithium give a higher yield (62%) than sodium (45%). The reduction of this compound is particularly slow, and hence the greater rate of reduction by lithium becomes significant. Bothner-By found that benzene is reduced by lithium 60 times faster than by sodium. 

This method has been extended to the reaction of PhCsCZnBr with aldehydes in the presence of stoichiometric amounts of the lithium alcoholate of 1.14 (R = Me). Divinylzincs (RCH=CH)2Zn react under similar conditions, or also in the presence of other lithium alcoholates [650]. Under precise experimental conditions, PhMgBr adds to aliphatic or aromatic aldehydes in the presence of zinc salts and 1.14 (R = n-Bu). The enantiomeric excesses in these additions are higher than 75%. Diaiylzincs react with aldehydes in the presence of aminoalcohols bearing a ferrocene skeleton 2.47 with a very high enantioselectivity [651, 652], Schiff bases have also been used as catalysts in such reactions [367], as have some titanium complexes (see below) [559,653,654,655],... 

In some cases, the use of lithium alcoholates of 1.14 (R = Me) gives improved results. For example, alkynyl- or alkenylzinc reagents can be used with these alcoholates [650,1167] (Figure 6.32), although alkenylzincs can react in the presence of 1.8 alone in catalytic amounts [1168,1169] (Figure 632). 

The basicity and nucleophilicity of incarcerated lithium alcoholates exceeds those of bulk phase alcoholates by several orders of magnitude resulting in efficient inner-molecular elimination or nucleophilic transacetalisation and formation of hemi-carcerands with one extended portal. In these innermolecular reactions, small structural changes of the guest have a sound effect on the reaction mode. 

In the previous section we have seen that the nucleophilicity and basicity of incarcerated lithium alcoholates strongly exceeds those of bulk phase alcoholates mainly as a result of the lack of aggregation and poor solvation by the host. As a consequence, innermolecular reaction involving lithium alcoholates are strongly accelerated. Several extrusion reactions have been studied inside container molecules and have highlighted additional ways how encapsulation inside a hemicarcerand may accelerate or decelerate inner phase reactions. 

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