Carbonyl compounds chloride

In the presence of titanium(IV) chloride or aluminum chloride, carbonyl compounds such as aldehydes, ketones, acetals, and acid halides are allylated with allylic silanes (eq (12)) [9]. The conjugate addition to enones is also reported (eq (13)) [10],... 

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). 

Various organotin reagents react with acyl and aroyl halides under mild conditions without decarbonylation to give carbonyl compounds[390,39l]. Alkyl- or alkenyltin reagents react with acyl and aroyl chlorides to give ketones[548.733,734]. One example is the preparation of the a,/3-dnsaturated 7-keto esters 860 and 861, carried out under a CO atmosphere[735]. The reaction has been applied intramolecularly to the synthesis of the macrocyclic keto... 

The reactivity of 2-methylselenazole toward carbonyl compounds is the same as its thiazoie homolog. Reaction of 2,4-dimethylselenazole with benzaldehyde in the presence of anhydrous zinc chloride as catalyst gives 4-methyl-2-styrylselenazoie [m.p. 74-75 C (19)] (Scheme 43). 

Acetaldehyde can be isolated and identified by the characteristic melting points of the crystalline compounds formed with hydrazines, semicarbazides, etc these derivatives of aldehydes can be separated by paper and column chromatography (104,113). Acetaldehyde has been separated quantitatively from other carbonyl compounds on an ion-exchange resin in the bisulfite form the aldehyde is then eluted from the column with a solution of sodium chloride (114). In larger quantities, acetaldehyde may be isolated by passing the vapor into ether, then saturating with dry ammonia acetaldehyde—ammonia crystallizes from the solution. Reactions with bisulfite, hydrazines, oximes, semicarb azides, and 5,5-dimethyl-1,3-cyclohexanedione [126-81 -8] (dimedone) have also been used to isolate acetaldehyde from various solutions. 

A particularly useful reaction has been the selective 1,2-reduction of a, P-unsaturated carbonyl compounds to aHyUc alcohols, accompHshed by NaBH ia the presence of lanthanide haUdes, especially cerium chloride. Initially appHed to ketones (33), it has been broadened to aldehydes (34) and acid chlorides (35). NaBH by itself gives mixtures of the saturated and unsaturated alcohols. 

Alkaline solutions of mononitroparaffins undergo many different reactions when stored for long periods, acidified, or heated. Acidification of solutions of mononitro salts is best effected slowly at 0°C or lower with weak acids or buffered acidic mixtures, such as acetic acid—urea, carbon dioxide, or hydroxyl ammonium chloride. If mineral acids are used under mild conditions, eg, dilute HCl at 0°C, decomposition yields a carbonyl compound and nitrous oxide (Nef reaction). 

These reversible reactions are cataly2ed by bases or acids, such as 2iac chloride and aluminum isopropoxide, or by anion-exchange resias. Ultrasonic vibrations improve the reaction rate and yield. Reaction of aromatic aldehydes or ketones with nitroparaffins yields either the nitro alcohol or the nitro olefin, depending on the catalyst. Conjugated unsaturated aldehydes or ketones and nitroparaffins (Michael addition) yield nitro-substituted carbonyl compounds rather than nitro alcohols. Condensation with keto esters gives the substituted nitro alcohols (37) keto aldehydes react preferentially at the aldehyde function. 

Such copolymers of oxygen have been prepared from styrene, a-methylstyrene, indene, ketenes, butadiene, isoprene, l,l-diphen5iethylene, methyl methacrjiate, methyl acrylate, acrylonitrile, and vinyl chloride (44,66,109). 1,3-Dienes, such as butadiene, yield randomly distributed 1,2- and 1,4-copolymers. Oxygen pressure and olefin stmcture are important factors in these reactions for example, other products, eg, carbonyl compounds, epoxides, etc, can form at low oxygen pressures. Polymers possessing dialkyl peroxide moieties in the polymer backbone have also been prepared by base-catalyzed condensations of di(hydroxy-/ f2 -alkyl) peroxides with dibasic acid chlorides or bis(chloroformates) (110). 

Carbonyl Compounds. Cychc ketals and acetals (dioxolanes) are produced from reaction of propylene oxide with ketones and aldehydes, respectively. Suitable catalysts iaclude stannic chloride, quaternary ammonium salts, glycol sulphites, and molybdenum acetyl acetonate or naphthenate (89—91). Lactones come from Ph4Sbl-cataly2ed reaction with ketenes (92). 

Manufacture. Trichloromethanesulfenyl chloride is made commercially by chlorination of carbon disulfide with the careful exclusion of iron or other metals, which cataly2e the chlorinolysis of the C—S bond to produce carbon tetrachloride. Various catalysts, notably iodine and activated carbon, are effective. The product is purified by fractional distillation to a minimum purity of 95%. Continuous processes have been described wherein carbon disulfide chlorination takes place on a granular charcoal column (59,60). A series of patents describes means for yield improvement by chlorination in the presence of dihinctional carbonyl compounds, phosphonates, phosphonites, phosphites, phosphates, or lead acetate (61). 

A significant advance in the synthesis of monoorganotin trihaHdes was the preparation of P-substituted ethyl tin trihaHdes in good yield from the reaction of stannous chloride, hydrogen haHdes, and a,P-unsaturated carbonyl compounds, eg, acryHc esters, in common solvents at room temperature and atmospheric pressure (153,154). The reaction is beHeved to proceed through a solvated trichlorostannane intermediate (155) ... 

Titanium(IV) is a powerful but selective Lewis acid which can promote the coupling of allylsilanes with carbonyl compounds and derivatives In the presence of titanium tetrachlonde, benzalacetone reacts with allyltnmethylsilane by 1,4-addition to give 4-PHENYL-6-HEPTEN-2-ONE. Similarly, the enol silyl ether of cyclopentanone is coupled with f-pentyl chloride using titanium tetrachlonde to give 2-(tert-PENTYL)CYCLOPENTANONE, an example of a-tert-alkylation of ketones. 

Epoxidation of aldehydes and ketones is the most profound utility of the Corey-Chaykovsky reaction. As noted in section 1.1.1, for an a,P-unsaturated carbonyl compound, 1 adds preferentially to the olefin to provide the cyclopropane derivative. On the other hand, the more reactive 2 generally undergoes the methylene transfer to the carbonyl, giving rise to the corresponding epoxide. For instance, treatment of P-ionone (26) with 2, derived from trimethylsulfonium chloride and NaOH in the presence of a phase-transfer catalyst Et4BnNCl, gave rise to vinyl epoxide 27 exclusively. ... 

Despite the increasing information on the photochemistry of 2,4-dienones and other unsaturated ketones, as well as on the ring-chain valence isomerism of halogen-substituted pyran and dihydi opyran systems,the data are still very scarce. The intermediate formation of pyrans valence-isomeric with unsaturated carbonyl compounds in the pyridine syntheses based on reactions of ammonia with aldehydes or ketones, advocated by various authors (cf. Section II,B,2,f), is still rather speculative. (See also Section II,B,2,e for the valence isomerism of 5-chloro-2,4-dienones with pyrylium chlorides.)... 

A methyl group in the 2-position of the selenazole ring shows the same reactivity as the analogous thiazoles toward carbonyl compounds. By reaction of 2,4-dimethylselenazole with benzaldehyde in the presence of anhydrous zinc chloride catalyst, 4-methyl-2-styryl-selcnazole (9), mp 74-75°C, could be prepared. ... 

The required nitrite esters 1 can easily be obtained by reaction of an appropriate alcohol with nitrosyl chloride (NOCl). The 3-nitroso alcohols 2 formed by the Barton reaction are useful intermediates for further synthetic transformations, and might for example be converted into carbonyl compounds or amines. The most important application for the Barton reaction is its use for the transformation of a non-activated C-H group into a functional group. This has for example been applied for the functionalisation of the non-activated methyl groups C-18 and C-19 in the synthesis of certain steroids. ... 

Methylsulfinyl carbanion (dimsyl ion) is prepared from 0.10 mole of sodium hydride in 50 ml of dimethyl sulfoxide under a nitrogen atmosphere as described in Chapter 10, Section III. The solution is diluted by the addition of 50 ml of dry THF and a small amount (1-10 mg) of triphenylmethane is added to act as an indicator. (The red color produced by triphenylmethyl carbanion is discharged when the dimsylsodium is consumed.) Acetylene (purified as described in Chapter 14, Section I) is introduced into the system with stirring through a gas inlet tube until the formation of sodium acetylide is complete, as indicated by disappearance of the red color. The gas inlet tube is replaced by a dropping funnel and a solution of 0.10 mole of the substrate in 20 ml of dry THF is added with stirring at room temperature over a period of about 1 hour. In the case of ethynylation of carbonyl compounds (given below), the solution is then cautiously treated with 6 g (0.11 mole) of ammonium chloride. The reaction mixture is then diluted with 500 ml of water, and the aqueous solution is extracted three times with 150-ml portions of ether. The ether solution is dried (sodium sulfate), the ether is removed (rotary evaporator), and the residue is fractionally distilled under reduced pressure to yield the ethynyl alcohol. 

Judging from the following electrostatic potential maps, which kind of carbonyl compound has the more electrophilic carbonyl carbon atom, a ketone or an acid chloride Which has the more nucleophilic carbonyl oxygen atom Explain. 

Carboxylic acids, RC02H, occupy a central place among carbonyl compounds. Not only are they valuable in themselves, they also serve as starting materials for preparing numerous acyl derivatives such as acid chlorides, esters, amides, and thioesters. In addition, carboxylic acids are present in the majority of biological pathways. We ll look both at acids and at their close relatives, nitriles (RC=N), in this chapter and at acyl derivatives in the next chapter. 

The Aggarwal group has used chiral sulfide 7, derived from camphorsulfonyl chloride, in asymmetric epoxidation [4]. Firstly, they prefonned the salt 8 from either the bromide or the alcohol, and then formed the ylide in the presence of a range of carbonyl compounds. This process proved effective for the synthesis of aryl-aryl, aryl-heteroaryl, aryl-alkyl, and aryl-vinyl epoxides (Table 1.2, Entries 1-5). 

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