Secondary with carbonyl compounds

Primary and secondary amines also react with epoxides (or in situ produced episulfides )r aziridines)to /J-hydroxyamines (or /J-mercaptoamines or 1,2-diamines). The Michael type iddition of amines to activated C—C double bonds is also a useful synthetic reaction. Rnally unines react readily with. carbonyl compounds to form imines and enamines and with carbo-tylic acid chlorides or esters to give amides which can be reduced to amines with LiAlH (p. Ilf.). All these reactions are often applied in synthesis to produce polycyclic alkaloids with itrogen bridgeheads (J.W. Huffman, 1967) G. Stork, 1963 S.S. Klioze, 1975). 

Reaction With Carbonyl Compounds. Primary and secondary nitroparaffins undergo aldol-type reactions with a variety of aldehydes and ketones to give nitro alcohols (11). Those derived from the lower nitroparaffins and formaldehyde are available commercially (see Nitro alcohols). Nitro alcohols can be reduced to the corresponding amino alcohols (see Alkanolamines). 

The well-known photopolymerization of acrylic monomers usually involves a charge transfer system with carbonyl compound as an acceptor and aliphatic tertiary amine, triethylamine (TEA), as a donor. Instead of tertiary amine such as TEA or DMT, Li et al. [89] investigated the photopolymerization of AN in the presence of benzophenone (BP) and aniline (A) or N-methylaniline (NMA) and found that the BP-A or BP-NMA system will give a higher rate of polymerization than that of the well-known system BP-TEA. Still, we know that secondary aromatic amine would be deprotonated of the H-atom mostly on the N-atom so we proposed the mechanism as follows ... 

Alcohols are among the most versatile of all organic compounds. They occur widely in nature, are important industrial 7, and have an unusually rich chemistry. The most widely used methods of alcohol synthesis start with carbonyl compounds. Aldehydes, ketones, esters, and carboxylic acids are reduced by reaction with LiAlH4. Aldehydes, esters, and carboxylic acids yield primary alcohols (RCH2OH) on reduction ketones yield secondary alcohols (R2CHOH). 

Nitrones have been generally prepared by the condensation of /V-hydroxylamines with carbonyl compounds (Eq. 8.40).63 There are a number of published procedures, including dehydrogenation of /V,/V-disubstituted hydroxylamines, / -alkylation of imines, and oxidation of secondary amines. Among them, the simplest method is the oxidation of secondary amines with H202 in the presence of catalytic amounts of Na2W04 this method is very useful for the preparation of cyclic nitrones (Eq. 8.41).64... 

Correlate reaction the reaction of telluronium salts with carbonyl compounds mediated by organoUthium reagents - formation of secondary alcohols... 

For primary alkyl phenyl ethers 47, their hthiation under catalytic conditions (DTBB, 5%) in THF at room temperature gave the expected alkyUithiums, which by reaction with carbonyl compounds afforded, after hydrolysis, the expected alcohols 48 (Scheme 15) . In this case, only the O—Caiiyi bond cleavage was observed . On the other hand, the reaction shown in Scheme 15 failed for secondary (R = i-Pr) or tertiary (R = f-Bu) starting materials. 

According to the Cd 18-90 AOCS ° official method, the ANV is 100 times the optical density measured in a 1 cm cell, at 350 nm, of a solution containing 1.00 g of oil in 100 ml of the test solution. The measured absorbance is due to Schiff bases (167) formed when p-anisidine (166) undergoes condensation reaction with carbonyl compounds, according to equation 55. The carbonyl compounds are secondary oxidation products of lipids, such as a, S-unsaturated aldehydes and ketones derived from the hydroperoxides (see Scheme 1 in Section n.A.2.c), and their presence points to advanced oxidation of the oil. 

The competition between insertion and hydrogen transfer is also crucial to the selectivity of the reaction of aluminium alkyls with carbonyl compounds. Aluminium alkyls, like organolithium compounds and Grignard reagents, can add to aldehydes and ketones to form secondary or tertiary alcohols, respectively. If the aluminium alkyl has a j -hydrogen, however, reduction of the carbonyl compound is a common side reaction, and can even become the main reaction [16]. Most authors seem to accept that reduction involves direct j5-hydrogen transfer to ketone. 

Resin-bound amines can be converted into imines [710,711] or enamines by reaction with carbonyl compounds (Entries 6 and 7, Table 3.39). Resin-bound enamines have also been prepared by Michael addition of resin-bound secondary amines to acceptor-substituted alkynes [712], by Hg(II)-catalyzed addition of resin-bound secondary amines to unactivated alkynes [713], by addition of C-nucleophiles to resin-bound imino ethers [714], and by chemical modification of other resin-bound enamines [712,713,715], Acceptor-substituted enamines ( push-pull alkenes) are not always susceptible to hydrolytic cleavage by TFA alone and might require aqueous acids to undergo hydrolysis [716]. 

Alcohol synthesis via the reaction of Grignard reagents with carbonyl compounds (Section 14.6) This is one of the most useful reactions in synthetic organic chemistry. Grignard reagents react with formaldehyde to yield primary alcohols, with aldehydes to give secondary alcohols, and with ketones to form tertiary alcohols. 

Since there have been some confusions in the nomenclature <1990AGE344, 1991CRV335>, it must be emphasized that (1) 1,2,3-trioxolanes are primary ozonides or moloxides (2) 1,2,4-trioxolanes are secondary or final ozonides and (3) Criegee s carbonyl oxide intermediate 1, 2 has been found theoretically to have a pronounced diradical character 3, not only in the gas phase, but also in solution in nonpolar solvents only its reaction with carbonyl compounds in solution has a polar character. Nevertheless, the name carbonyl oxide is so well entrenched that it will continue to be used for intermediates 1-3. 

L-Proline is perhaps the most well-known organocatalyst. Although the natural L-form is normally used, proline is available in both enantiomeric forms [57], this being somewhat of an asset when compared to enzymatic catalysis [58], Proline is the only natural amino acid to exhibit genuine secondary amine functionality thus, the nitrogen atom has a higher p Ka than other amino acids and so features an enhanced nucleophilicity compared to the other amino acids. Hence, proline is able to act as a nucleophile, in particular with carbonyl compounds or Michael acceptors, to form either an iminium ion or enamine. In these reactions, the carboxylic function of the amino acid acts as a Bronsted acid, rendering the proline a bifunctional catalyst. 

Methyl and primary isocyanides are easily lithiated and react with carbonyl compounds to form heterocycles such as 102. Secondary isocyanides (with the exception of small rings) cannot be lithiated.69... 

Allylindium reagents bearing substituents at the 7-position react with carbonyl compounds in organic and aqueous media regioselectively at the 7-position, via a six-membered transition state, to afford the corresponding branched homoallylic alcohols, if no sterically bulky carbonyl or allyl substituent is involved.102 For example, the indium-mediated reaction of aldehydes with 3-bromo-l-cyano-l-propene proceeds readily in water to give cr-cyano-f3-ethylenic secondary alcohols (Scheme 4).103... 

Secondary amines react with carbonyl compounds to form enamines ... 

Reductive alkylation of ammonia may proceed under mild conditions over nickel catalysts. In examples using Raney Ni, temperatures ranging from 40 to 150°C and hydrogen pressures of 2-15 MPa have been used to obtain satisfactory results.3,4 In general, the reductive alkylation of ammonia with carbonyl compounds may produce primary, secondary, and tertiary amines, as well as an alcohol, a simple hydrogenation product of the carbonyl compound (Scheme 6.1). The selectivity to respective amine depends primarily on the molar ratio of the carbonyl compound to ammonia, although the nature of catalyst and structure of the carbonyl compound are also important factors for the selectivity. As an example, the reaction of benzaldehyde in the presence of 1 equiv of ammonia in ethanol over Raney Ni gave benzylamine in an 89.4% yield while with 0.5 molar equivalent of ammonia dibenzylamine was obtained in an 80.8% yield (eq. 6.1).4... 

The simplest ylide generation method among the deprotonation route (Section II,D) consists of the condensation of N-substituted a-amino esters with carbonyl compounds. This procedure must be especially useful for utilization in intramolecular cycloadditions because the substrates for the cycloadditions are simply prepared in situ by reacting the carbonyl compounds (or secondary amines) bearing a trapping chain with secondary amines (or carbonyl compounds). 

As indicated previously, primary and secondary amines can also react with carbonyl compounds to form a mixture of compounds containing small molecules and polymers. The small molecule compounds obtained from an aldose and an amine have the common name Amadori products because the Amadori rearrangement is involved in their formation. The compounds generated from ketoses and amines are known as Heyns products (although the differentiation Amadori/Heyns is not always considered). The mechanism for the reaction of primary amines with a reducing sugar can be formulated as follows ... 

Leuckart-Wallach reaction. Reductive alkylation of ammonia or of primary or secondary amines with carbonyl compounds and formic acid or formamides as reducing agents. 

Interligand asymmetric induction. Group-selective reactions are ones in which heterotopic ligands (as opposed to heterotopic faces) are distinguished. Recall from the discussion at the beginning of this chapter that secondary amines form complexes with lithium enolates (pp 76-77) and that lithium amides form complexes with carbonyl compounds (Section 3.1.1). So if the ligands on a carbonyl are enantiotopic, they become diastereotopic on complexation with chiral lithium amides. Thus, deprotonation of certain ketones can be rendered enantioselective by using a chiral lithium amide base [122], as shown in Scheme 3.23 for the deprotonation of cyclohexanones [123-128]. 2,6-Dimethyl cyclohexanone (Scheme 3.23a) is meso, whereas 4-tertbutylcyclohexanone (Scheme 3.23b) has no stereocenters. Nevertheless, the enolates of these ketones are chiral. Alkylation of the enolates affords nonracemic products and O-silylation affords a chiral enol ether which can... 

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