Alcohol organometallic primary

In order to improve the fair enantiosectivity described above, the coordination between the chiral organometallic complex, the electron-donating oxygen, and the n-bond of the styryl moiety were reinforced by switching from cinnamyl alcohol to its mixed acetal derived from 2-methoxypropene. For this latter case the carbolithiation takes place at -50°C (instead of 0°C with cinnamyl alcohol) and primary or secondary alkyUithiiuns (in hexane or cumene) give the addition product in 70-80% yield, with ees of 94 and 90%, respectively [39, 40] (Scheme 19). With n-butyllithium, the use of 10% sparteine led to 67% yield (with an ee of 92 %), whereas use of 1 % sparteine gave 50% yield (with an ee of 85%) [39]. 

How many different poly(organophosphazenes) are accessible by this synthesis route Taking into account the available alcohols, phenols, primary and secondary amines, and organometallic reagents, it seems clear that the phosphazene homopolymers accessible by known synthesis routes rival in numbers all the known organic polymers. 

Grignard reagents react with ethylene oxide to yield primary alcohols containing two more carbon atoms than the alkyl halide from which the organometallic compound was prepared... 

The method is not restricted to secondary aryl alcohols and very good results were also obtained for secondary diols [39], a- and S-hydroxyalkylphosphonates [40], 2-hydroxyalkyl sulfones [41], allylic alcohols [42], S-halo alcohols [43], aromatic chlorohydrins [44], functionalized y-hydroxy amides [45], 1,2-diarylethanols [46], and primary amines [47]. Recently, the synthetic potential of this method was expanded by application of an air-stable and recyclable racemization catalyst that is applicable to alcohol DKR at room temperature [48]. The catalyst type is not limited to organometallic ruthenium compounds. Recent report indicates that the in situ racemization of amines with thiyl radicals can also be combined with enzymatic acylation of amines [49]. It is clear that, in the future, other types of catalytic racemization processes will be used together with enzymatic processes. 

Payne rearrangement. The Payne rearrangement2 of a primary cts-2,3-epoxy alcohol to a secondary 1,2-epoxy alcohol usually requires a basic aqueous medium, but it can be effected with BuLi in THF, particularly when catalyzed by lithium salts. As a consequence, the rearrangement becomes a useful extension of the Sharpless epoxidation, with both epoxides available for nucleophilic substitutions. Thus the more reactive rearranged epoxide can be trapped in situ by various organometallic nucleophiles. Cuprates of the type RCu(CN)Li are particularly effective for this purpose, and provide syn-diols (3).3... 

Primary and tertiary alcohols are obtained conveniently from esters by the reduction of LiAlH4 and two molar equivalents of organometallic reagents (R MgX or R Li), respectively (see Sections 5.7.22 and 5.5.5). A less powerful reducing agent, diisobutylaluminium hydride (DIBAH), reduce an ester to an aldehyde (see Section 5.7.22). 

Addition of organometallic reagent to formaldehyde preparation of primary alcohols... 

Reaction of organometallic compounds with carbonyl compounds a. primary alcohols from methanal (formaldehyde)... 

The synthetic method (b) combines the formation of a primary or secondary alkynol [from formaldehyde or an aldehyde respectively and an organometallic acetylenic reagent (Section 5.4.2, p. 532)] with the semihydrogenation of the triple bond to a double bond. As noted in Section 5.2.2, p. 493, appropriate selection of catalyst is necessary in the hydrogenation step to ensure the formation of either the ( )- or the (Z)-isomer. The specific formation of the allylic alcohol, CH2=CH-CH(OH),R, is from a vinylmagnesium halide (Expt 6.41) and an aldehyde. 

Primary, secondary, and tertiary alkyl halides also can be reduced with dissolving metals. The primary reduction product is an organometallic compound. Whether the latter is formed quantitatively or whether it is converted into the corresponding hydrocarbon by protonation depends on the solvent. The organometallic compound is stable in aprotic solvents (hexane, ether, THF), while it is protonated in protic solvents (HOAc, alcohols). 

The reaction of an organometallic reagent with formaldehyde produces a primary alcohol ... 

Making primary alcohols from organometallics and formaldehyde... 

Perhaps the greatest use of organometallic compounds is in the transfer of alkyl groups to carbon atoms that are bound in organic molecules. For example, the reaction of a Grignard reagent with a primary alcohol can be shown as... 

A convincing reaction from organometallic chemistry was a long time coming. Petasis and Zavialov now report [7a-b] that vinylboronic acids 18 [7c-d], which are readily accessible and easy to handle, can participate in a three-component reaction with primary and secondary amines 19 and with a-keto acids 20. The process, which proceeds at room temperature, leads to )ff,y-unsaturated a-amino acids 21 in good yields. The reaction of vinylboronic acid 22 with the chiral amino alcohol 23 and glyoxylic... 

The dialkylzinc additions catalyzed by N,N-di-n-alkylnorephedrines (most typically DBNE) are not limited to primary organometallic reagents. Diisopropylzinc (with a secondary alkyl substituent) adds to benzaldehyde in the presence of a catalytic amount of DBNE to afford the corresponding alcohol with high ee (entry 4). The reaction of diisopropylzinc in the presence of other types of catalysts may result in the reduction of aldehydes. 

This reaction is initiated by varicais compounds such as amine, water, alcohol, metal alkoxide, organometallic compound etc. The reaction initiated by primary amine is one of the best studied, and proceeds by the repetition of the attack of primary amino group towards the 5-carbonyl group of NCA. 

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