Lithium aluminum hydride, reduction with

Give the structure of an ester that will yield a mixture contain mg equimolar amounts of 1 propanol and 2 propanol on reduction with lithium aluminum hydride... 

Reduction with lithium aluminum hydride (Sec tion15 3) Lithium alumi num hydride cleaves es ters to yield two alcohols... 

In general, if the desired carbon—phosphoms skeleton is available in an oxidi2ed form, reduction with lithium aluminum hydride is a powerful technique for the production of primary and secondary phosphines. The method is appHcable to halophosphines, phosphonic and phosphinic acids as well as thein esters, and acid chlorides. Tertiary and secondary phosphine oxides can be reduced to the phosphines. 

An aiyl methane- or toluenesulfonate ester is stable to reduction with lithium aluminum hydride, to the acidic conditions used for nitration of an aromatic ring (HNO3/HOAC), and to the high temperatures (200-250°) of an Ullman reaction. Aiyl sulfonate esters, formed by reaction of a phenol with a sulfonyl chloride in pyridine or aqueous sodium hydroxide, are cleaved by warming in aqueous sodium hydroxide. ... 

During the course of these mechanistic studies a wide range of possible applications of this reaction have been revealed. When the reduction is carried out with lithium aluminum deuteride and the anion complex decomposed with water, a monodeuterio compound (95) is obtained in which 70% of the deuterium is in the 3a-position. Reduction with lithium aluminum hydride followed by hydrolysis with deuterium oxide yields mainly (70 %) the 3j5-di-epimer (96), while for the preparation of dideuterio compounds (94) both steps have to be carried out with deuterated reagents. ... 

In certain cases this reduction (with lithium aluminum hydride) takes a different course, and olefins are formed. The effect is dependent on both the reagent concentration and the steric environment of the hydrazone. Dilute reagent and hindered hydrazone favor olefins borohydride gives the saturated hydrocarbon. The hydrogen picked up in olefin formation comes from solvent, and in full reduction one comes from hydride and the other from solvent. This was shown by deuteriation experiments with the hydrazone (150) ... 

The configurations assigned to (8) and (9) were established by comparison with the products resulting from epoxidation of 3-methyl-5a-cholest-2-ene followed by reduction with lithium aluminum hydride to the alcohol (9). The usual /ra 5-diaxial epoxide opening requires that the hydroxyl group, formed by reduction, is axial as shown in (9). 

J -Dehydroquinolizidine reacts with the enantiomeric (—)- and (-l-)-menthyl chloroformates forming (—)- and (-l-)-menthoxycarbonyl- -dehydroquinolizidines. These can be reduced as such or in the form of their immonium salts with sodium borohydride to (—)- and (+)-l-menthoxy-carbonylquinolizidines, which give (+)- and (-)-lupinin, respectively, on reduction with lithium aluminum hydride (243). The optical yield of the asymmetric reduction is about 10%. 

Grignard and alkyl lithium reagents were found to add to the carbonyl group of a tricyclic vinylogous amide. However, the same compound underwent the usual vinylogous reduction with lithium aluminum hydride (712). Grignard additions to di- and trichloroenamines gave a-chloro- and dichloroketones (713). 

The chemical reduction of enamines by hydride again depends upon the prior generation of an imonium salt (111,225). Thus an equivalent of acid, such as perchloric acid, must be added to the enamine in reductions with lithium aluminum hydride. Studies of the steric course (537) of lithium aluminum hydride reductions of imonium salts indicate less stereoselectivity in comparison with the analogous carbonyl compounds, where an equatorial alcohol usually predominates in the reduction products of six-membered ring ketones. 

Vinylogous amides undergo reduction with lithium aluminum hydride, by Michael addition of hydride and formation of an enolate, which can resist further reduction. Thus -aminoketones are usually produced (309, 563,564). However, the alternative selective reduction of the carbonyl group has also been claimed (555). 

Aryl and alkyl trimethylsilyl ethers can often be cleaved by refluxing in aqueous methanol, an advantage for acid- or base-sensitive substrates. The ethers are stable to Grignard and Wittig reactions and to reduction with lithium aluminum hydride at —15°. Aryl -butyldimethylsilyl ethers and other sterically more demanding silyl ethers require acid- or fluoride ion-catalyzed hydrolysis for removal. Increased steric bulk also improves their stability to a much harsher set of conditions. An excellent review of the selective deprotection of alkyl silyl ethers and aryl silyl ethers has been published. ... 

Reduction with lithium aluminum hydride allows a differentiation from the isomeric nitrones. Whereas 2-tert-butyl-3-phenyloxazirane (9) gives benzylidene-tert-butylamine [Eq. (10)], reduction of the isomeric nitrone leads to iV-benzyl-xV-fert-butylbydroxylaminc [Eq. 

Acylation of norephedrine (56) with the acid chloride from benzoylglycolic acid leads to the amide (57), Reduction with lithium aluminum hydride serves both to reduce the amide to the amine and to remove the protecting group by reduction (58), Cyclization by means of sulfuric acid (probably via the benzylic carbonium ion) affords phenmetrazine (59), In a related process, alkylation of ephedrine itself (60) with ethylene oxide gives the diol, 61, (The secondary nature of the amine in 60 eliminates the complication of dialkylation and thus the need to go through the amide.) Cyclization as above affords phendimetra-zine (62), - Both these agents show activity related to the parent acyclic molecule that is, the agents are CNS stimulants... 

Butyl alcohol in synthesis of phenyl 1-butyl ether, 46, 89 1-Butyl azidoacetate, 46, 47 hydrogenation of, 46, 47 1-Butyl chloroacetate, reaction with sodium azide, 46, 47 lre l-4-i-BUTYLCYCLOHEXANOL, 47,16 4-(-Butylcyclohexanonc, reduction with lithium aluminum hydride and aluminum chloride, 47, 17 1-Butyl hypochlorite, reaction with cy-clohexylamine, 46,17 l-Butylthiourea, 46, 72... 

The condensed l//-l,2-diazepines 12 are transformed into the 3//-tautomers 24 by reduction with lithium aluminum hydride to give 23, followed by dehydrogenation with 4-phenyl-4//-1,2,4-triazole-3,5-dione.146... 

Since double bonds may be considered as masked carbonyl, carboxyl or hydroxymethylene groups, depending on whether oxidative or reductive methods are applied after cleavage of the double bond, the addition products from (E)-2 and carbonyl compounds can be further transformed into a variety of chiral compounds. Thus, performing a second bromine/lithium exchange on compound 4, and subsequent protonation, afforded the olefin 5. Ozonolysis followed by reduction with lithium aluminum hydride gave (S)-l-phenyl-l,2-ethanediol in >98% ee. 

Compared to the lithium enolates of l and 5, the higher stereoselectivity obtained by the Mukaiyama variation is, in general, accompanied by reduced chemical yields. The chiral alcoholic moieties of the esters 3 and 7 can be removed either by reduction with lithium aluminum hydride (after protection of the earbinol group) or by aqueous alkaline hydrolysis with lithium hydroxide to afford the corresponding carboxylic acid. In both cases, the chiral auxiliary reagent can be recovered. 

The lithium cnolate generated by deprotonation of 2-/m-butyl-6-methyl-l,3-dioxan-4-onc, readily available from polyhydroxybutyric acid (PHB), predominantly affords the diastereo-mers 7 when reacted with aldehydes. The diastereomeric ratios of aldol adducts 7/8, produced by reactions with aliphatic aldehydes, range from 87.5 12.5 to >99 1. Pure diastereoiners7are obtained by recrystallization in 25-74% yield116-118. Only marginal diastereoselectivities with respect to the carbinol center are obtained with aromatic aldehydes111-119. Benzoylation of the dioxanones 7, followed by reduction with lithium aluminum hydride, affords enan-tiomerically and diastereomerically pure triols 9 in >85% yield 11. ... 

The combination of the enantiomerically pure 7V-methylephedrine derived silylketene acetal l-[(l/ ,2S)-2-dimethylamino-1-phenylpropoxy]-l-triniethylsilyloxy-l-propene with the chiral aldehyde (,R)-3-benzyloxy-2-methylpropanal leads, after reduction with lithium aluminum hydride, to the formation of a single 1,3-pentanediol 9 ( matched pair ). 

E. L. Eliel, Reductions with Lithium Aluminum Hydride — Aluminum Halide Combinations, Record Chem. Progress 22, 129 (1961). 

The same nonpolar conformation can be achieved by conversion to bicyclic structures. 1,4-Cyclo-addition of ethylene to anthracene-9-carboxylic acid gives acid 68. Successive conversion to the N-methylamide, via the acid chloride, followed by reduction with lithium aluminum hydride produced... 

In this series, too, replacement of the N-methyl by a group such as cyclopropylmethyl leads to a compound with reduced abuse potential by virtue of mixed agonist-antagonist action. To accomplish this, reduction of 24 followed by reaction with tertiary butylmagnesium chloride gives the tertiary carbinol 27. The N-methyl group is then removed by the classic von Braun procedure. Thus, reaction with cyanogen bromide leads to the N-cyano derivative (28) hydrolysis affords the secondary amine 29. (One of the more efficient demethylation procedures, such as reaction with ethyl chloroformate would presumably be used today.) Acylation with cyclopropylcarbonyl chloride then leads to the amide 30. Reduction with lithium aluminum hydride (31) followed by demethylation of the phenolic ether affords buprenorphine (32).9... 

A rather complex fused isoindoline (87) has been found to show good anorectic activity. This substance differs from other anorectic agents by not being a p-phenethylamine analogue. Preparation of this compound starts by reaction of a substituted benzoyl-benzoic acid (82) with ethylene diamine. The product (84) can be rationalized as being the aminal from the initially obtained monoamide 83. This is then subjected to reduction with lithium aluminum hydride... 

Lange and Bosch<109) reported the interesting intramolecular oxetane formation shown below. Reduction with lithium aluminum hydride afforded m is-9-decalol (32%) ... 

Dubois et al. [4] describe the synthesis of organophosphine dendrimers via the sequential addition of diethylvinyl phosphonate to primary phosphines followed by reduction with lithium aluminum hydride (Scheme 2). Metallation of... 

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