Cyclic ketones macrocyclic

Dianions derived from cyclic a-nitro ketones have been used for the preparation of the natural product phoracanthlide and related macrocyclic lactones (see Scheme 5.2).13 Alkylation of dianion of a-nitro cyclic ketones is followed by radical denitration with Bu3SnH (see Section... 

Imines derived from macrocyclic ketones (C10 to C 15 ) and (- )-(S)-a-(methoxymcthyl)benzene-ethanamine are successfully deprotonated using LDA ( —25 JC. THF. 1 h)9. In contrast to azaenolates of C0- to C8-membered cyclic ketones, which show only E geometry, Z-isomers are observed with macrocyclic imines. As evident from H-NMR data, azaenolates of cyclodecanone imines generated under these conditions are a mixture of E- and Z-isomers (33 66), whereas azaenolates of cyclododecanone and cyclopenladecanone imines arc formed as the pure. E-isomers (see Table 3). Upon heating the solutions of metalated imines to reflux for 1 hour, complete isomerization to the thermodynamically more stable Z-isomers occurs. 

The Baeyer-Villiger oxidation can be used to convert large ring cyclic ketones to macrocyclic lactones, Lactones can be precursors of cyclic ethers. Chiral ketone (37) was oxidized to lactone (38) and subsequently stereoselectively converted to the c, r-2,8-disubstituted oxocane (39 Scheme 10). ... 

In contrast with medium-sized cyclic ketones, alkylation of macrocyclic ketones can afford either optical antipode depending on whether the lithioenamine is formed via kinetic ( -) or thermodynamic conditions (Z-enamine) (eq 3). Optically active a-alkyl macrocyclic ketones have been formed in 30-82% enantiomeric... 

Cyclic ketones. 1,5-Dienes undergo silylcarbonylation and cyclization in tandem in the presence of CO. Macrocyclic ketolactones are acquired from (o-iodoalkyl acrylates by an intramolecular radical Michael reaction under similar conditions. 

Under conditions of high dilution to prevent intermolecular reactions, two allylic halide groups in the same molecule can be coupled to give a cyclic product. Macrocyclic lactones have been made in this way. Coupling occurs only at the primary centres. Note that the nickel reagents do not attack ester groups. Neither do they react with acid chlorides, ethers, nitriles, olefins or alkyl, aryl or vinyl chlorides (in contrast to bromides or iodides). Aldehydes and cyclic ketones are attacked, however, above 40°C affording homoallylic alcohols. 

Macrocycle Synthesis Cyclic Ketones, Ketoalkenes, Diketones and Dienes of Ring Size C21 to C26." Foibes. M.D.E. Dang, Y. Org. Prep. Proceed. Ira., 1993, 25, 309... 

In addition to the above, a variety of macrocyclic aromatic compounds, including cyclic esters [102], ethers [103], amides [104,105], ether ketones [106], and ether ether ketones [107,108] have also been synthesized extensively in the past decade. 

In 1973, Van Dorp et al. found a number of interesting macro-cyclic compounds, including some with both double and triple unsaturated bonds (26), but made no attempt to determine their biological significance. They compared the macrocyclic ketones and the fatty acids found in civet and muskrat gland and concluded that there is evidently no correlation between the macrocyclic ketone composition and the fatty acid composition. For example, cycloheptadecanone was the most prominent peak in the muskrat gland (41% of the macrocyclic ketones), whereas the stearic acid from which it could have been formed, was among the minor components (3%) of the fatty acids. 

Myriad polydentate aza-macrocycles have been reported 41. The extent of the subject forces limitation of this discussion to only macrocycles containing a pyridine or dipyridine subunit. Most of these coronands have been synthesized by a SchifF base condensation of an aldehyde or ketone with a hfc-primary amine in the presence of a metal ion. The metal ion acts as a template, resulting in dramatic increases in yield of the desired cyclic product over linear polymerization products42 46. Lindoy and Busch45 have described this effect in two ways, kinetic and thermodynamic. If the metal ion controls the steric course of a series of stepwise reactions, the template effect is considered to be kinetic. If the metal ion influences an equilibrium in an organic reaction sequence by coordination with one of the reactants, the template effect is termed thermodynamic. It is the kinetic effect that is believed to be operative in most metal ion-assisted (in situ) syntheses of... 

Another general method for the introduction of a nitrogen atom into a macrocyclic skeleton is via the Beckmann reaction. Rearrangement of cyclotridecanone oxime led to cyclic lactam, which was reduced to amine by lithium aluminium hydride (LAH). Further substitution yielded 14-membered mutuporamine <1999TL5401>. Dieckmann condensation was used for the preparation of 14-membered aza ketone 15 <1999JA2919>, but no experimental details were given. 

Extension of the low-valent titanium dicarbonyl coupling reaction to ketoesters leads to cyclic enol ethers, and hydrolysis of these affords the corresponding cycloalkanones. This methodology has been applied to the synthesis of various natural products, as exemplified by the preparation of the highly unsaturated C(14) macrocyclic ketone shown below. 

The cyclic tetraazadienes were first discovered by Curtis (Curtis, 1960 Curtis and House, 1961). These macrocycles were prepared by reacting 1,2-diaminoethane, 1,2-diaminopropane, or 1,3-diaminopropane with acetone, methyl ethyl ketone, propionaldehyde, n-butyraldehyde, isobutyraldehyde, or other small carbonyl compounds in the presence of Ni(II) or Cu(II) (Blight and Curtis, 1962 House and Curtis. 1962, 1964a, 1964b). Similar tetraaza macrocycles can be isolated from the reaction of triethylenetetraamine and the carbonyl compound in the presence of the metal template ions (Curtis... 

For the first time we report the synthesis of macrocycles like calixpyrrole, cyclotriveratrylene (CTV), cyclotetraveratrylene (CTTV), porphyrine ete over molecular sieve as a catalyst. Calixpyrroles are synthesized from pyrrole and a ketone like acetone over MCM-41 under reflux conditions using suitable solvent. In case of MCM-41 cyclic calixpyrroles were obtained. On the other hand due to shape selectivity in case of Y zeolite linear di-, tri- and tetra- polypyrroles were obtained and cyclic tetramers were not observed. The mechanism of the synthesis of calixpyrrole is either by the dimerization of dimer with simultaneous cyclization to cyclic tetramer or cyclization of linear tetramer via recoil phenomenon. 

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