Ketones conjugated diene synthesis

Nickel-bpy and nickel-pyridine catalytic systems have been applied to numerous electroreductive reactions,202 such as synthesis of ketones by heterocoupling of acyl and benzyl halides,210,213 addition of aryl bromides to activated alkenes,212,214 synthesis of conjugated dienes, unsaturated esters, ketones, and nitriles by homo- and cross-coupling involving alkenyl halides,215 reductive polymerization of aromatic and heteroaromatic dibromides,216-221 or cleavage of the C-0 bond in allyl ethers.222... 

Acetoacetic Ester Synthesis Section 20.4 Addition of an Alcohol to an Aldehyde or a Ketone Section 18.9 Figure 18.5 Addition of a Carbene to an Alkene Section 11.8 Addition to a Conjugated Diene Section 11.13 Addition of a Grignard Reagent to an Aldehyde or a Ketone Section 18.6... 

The overall procedure of the spiro y-lactone and 7-lactone synthesis can be considered as a molecular-assembling process in which three simple independent species (i.e., a conjugated diene, a ketone, and carbon dioxide) are used to build a complex organic molecule in a well-controlled fashion. 

Table 4 Synthesis of Spiro y-Lactones from Conjugated Dienes, Ketones, and COj...

Topics that have formed the subjects of reviews this year include contemporary issues in electron transport research, dynamics of bimolecular photoelectron transfer reactions, photophysical properties of functionalised fullerene derivatives, carbon-carbon bond formation via radical ions, photoinduced electron transfer processes in ketone, aldehyde, and ester synthesis, photochemical reactions between arenenitriles and benzylic donors, photo-oxidation of conjugated dienes, photoredox reactions of aromatic nitro compounds, electron transfer-mediated photochemistry of some unsaturated nitrogen-containing compounds, reactions of 02( Ag), carbon dioxide activation by aza-macrocyclic complexes, and photochromism of chalcone derivatives. ... 

Salomon and his coworkers have over the years studied the influence of copper(I) triflate on the cyclization of non-conjugated dienes. In the present example the diene (170) is converted readily on irradiation in the presence of the catalyst and affords the alcohol (171). This is oxidised to the corresponding ketone. The intramolecular cyclization of the diene (172), using a copper triflate catalyst, affords the straight (2-1-2) adduct (173). This cyclization was used as an approach to the synthesis of RobustadiaJ B. However, it was shown that the proposed structure of the natural product was wrong and that the robustadials should have the camphahe moiety in their structure as shown in (174). ... 

The olefin synthesis has been extended to the preparation of conjugated dienes from the tosylhydrazoncs of /3-unsatnrated ketones.61 The reaction is particularly useful for preparation of 1,3-cyclohexadienes as shown by the preparation of (8). /3-lononc tosylhydrazone was converted into the triene (9). The method cannot be used to prepare allenes. Further experiments indicated that the eliminated a-hydro-gen must be part of a methylene or methyl group. Methyllithium was found to be superior to -butyllithium. 

Tanino and Kuwajima used a guanidine base promoted elimination reaction in the synthesis of ingenol (110) [33]. Reaction of ketone 108 with MTBD resulted in an elimination reaction and subsequent isomerization to give conjugated diene 109, which was efficiently led to ingenol (110) (Scheme 7.23). 

Synthesis of Fused Carbocycles, p-y-Unsaturated Ketones, and 3-Cyclopentenols from Conjugated Diene-Magnesium Reagents... 

Table 4.9 Synthesis of spiro-y-lactones from conjugated diene, ketones, and CO2.

Several syntheses of aldehydes and ketones based on the insertion of carbon monoxide have been reported. Reaction of norbornadiene with monosubstituted acetylenes in the presence of octacarbonyldicobalt gives the fused cyclopen-tenone (35) in high yield conjugate addition of a cuprate and vacuum pyrolysis completes a simple synthesis of 2,3-disubstituted cyclopent-4-enones (36) (Scheme 30)." Conjugated dienes with methyl iodide in the presence of the same cobalt reagent yield conjugated dienones (37) [equation (8)]." In a review of carbonyl insertion reactions, the same reagent is reported to catalyse the reaction... 

Bicyclo[2.2.2]octanes can be obtained by a simple method The synthesis of the griseofulvin system has been accomplished in essentially one operation by a double Michael addition to an ethynyl vinyl ketone The sesquiterpenes longifolene with its highly intricate skeleton, and caryophyllene have yielded to ingenious synthetic endeavors. Cyclobutene ring closures by photoisomerization of conjugated dienes are used for the construction of various isocyclic and heterocyclic systems... 

Conjugated dienes can be selectively hydrated to ketones in the presence of cationic ruthenium complexes with bipyridyl ligands. The role of ruthenium is to catalyze the isomerization of allylic alcohols formed by the addition of water to diene. This method allows one to convert butadiene to methyl ethyl ketone in high yield [187]. Hydration of triple bonds is one of the oldest catalytic processes of organic chemistry. Though this reaction has no industrial value, it can serve as a tool of fine organic synthesis. The hydration can be catalyzed by rhodium salts under phase-transfer conditions [188]. The more exotic process of the hydrolysis of phenylacetylene to toluene and carbon monoxide catalyzed by ruthenium complex should also be mentioned [189] ... 

Allylic phosphonium ylides can also be generated in situ by the nucleophilic attack of phosphines on aziridines (or epoxides) followed by a set of proton transfers. On the basis of these reaction pathways, Hou et al. have realized a slightly E selective synthesis of conjugated dienes from aldehydes (or ketones) and aziridines (or epoxides) in the presence of tributylphosphine (Scheme 27) [122]. 

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