Dienes carbonyl derivatives

Conjugated dienes can be acylated by treatment with acyl- or alkylcobalt tetracarbonyls, followed by base-catalyzed cleavage of the resulting jt-allyl carbonyl derivatives. The reaction is very general. With unsymmetrical dienes, the acyl... 

In the general context of donor/acceptor formulation, the carbonyl derivatives (especially ketones) are utilized as electron acceptors in a wide variety of reactions such as additions with Grignard reagents, alkyl metals, enolates (aldol condensation), hydroxide (Cannizzaro reaction), alkoxides (Meerwein-Pondorff-Verley reduction), thiolates, phenolates, etc. reduction to alcohols with lithium aluminum hydride, sodium borohydride, trialkyltin hydrides, etc. and cyloadditions with electron-rich olefins (Paterno-Buchi reaction), acetylenes, and dienes.46... 

Abstract The basic principles of the oxidative carbonylation reaction together with its synthetic applications are reviewed. In the first section, an overview of oxidative carbonylation is presented, and the general mechanisms followed by different substrates (alkenes, dienes, allenes, alkynes, ketones, ketenes, aromatic hydrocarbons, aliphatic hydrocarbons, alcohols, phenols, amines) leading to a variety of carbonyl compounds are discussed. The second section is focused on processes catalyzed by Pdl2-based systems, and on their ability to promote different kind of oxidative carbonylations under mild conditions to afford important carbonyl derivatives with high selectivity and efficiency. In particular, the recent developments towards the one-step synthesis of new heterocyclic derivatives are described. 

Certain allyl cations react quite efficiently with nonactivated alkenes to give cyclobutanes. Such cations can be generated by Lewis acid catalyzed dehalogenation of allyl halides, protonation of conjugated dienes and Lewis acid eomplexation of conjugated carbonyl derivatives. For example, 2-chloro-2,4-dimethylpent-3-ene ( ) reacts with alkenes in the presence of zinc(II) chloride to give the corresponding cyclobulanes.1 Alkyl substitution of the allyl cation at the 2-position results in [3 + 2]-cycloaddition products. 

Just as with neutral arene or olefin metal carbonyls, the cationic analogs are useful intermediates for the preparation of other substituted cations. This is because the organic moiety is often readily displaced by another ligand and, further, allows carbonyl derivatives to be prepared, which may not be readily accessible by direct reaction (dien = diethylene triamine). 

The oxo-HDA reaction of 2-carbonyl derivatives of pyridine 1-oxide with electron-rich dienes catalysed by bisoxazoline Cu(II) complexes proceeds by a Mukaiyama-aldol route and affords dihydropyran-4-ones 33 in good yield and excellent enantioselectivity <07JOC240>. 

R)- and (S)-f-Butyl-5-methylene-l,3-dioxolan-4-one, a Chiral a-Alkoxy Acrylate. It is also possible to introduce an ex-ocyclic double bond onto the dioxolanone ring, as in compounds (9)-(ll), derived from lactic and malic - acids. These a,3-unsaturated carbonyl derivatives are acceptors for radical additions and undergo cycloadditions with dienes and heterodienes. The Diels-Alder adduct (12) of ent-(9) with cyclopentadiene is formed with exo selectivity (96 4) and serves as aprecursor to norbomenone (13). Cycloadduct (14), obtained from methylenedioxolanone (9) and an open-chain triene, is also the result of an exo addition and is used in tetronolide synthesis. ... 

The vast majority of work on asymmetric Diels-Alder reactions deals with additions of 1,3-dienes to a, -alkenic carbonyl derivatives XXI) where the chirophore R is attached to the carbonyl group eiAer directly or via a heteroatom X, permitting subsequent removal of the auxiliary (e.g. by attack of a nucleophile Nu Scheme 75). 

Many other addition reactions of olefins, dienes, and acetylenes are known, which are catalyzed by metal carbonyls including Ni(CO)4, Fe(CO)5, and Co2(CO)8 and by carbonyl derivatives such as hydrocarbonyls or phosphine-substituted carbonyls. Among these are the hydro-carboxylation, hydroesterification, and hydrocyanation of olefins the synthesis of hydroquiniones from acetylenes, carbon monoxide, and water ... 

Alkylation of hydrazine with a, 3-unsaturated carbonyl derivatives or carbonyl derivatives with a leaving group in the p-position provides pyrazole derivatives. For example, treatment of the tosylate (77), obtained from L-serine, with anhydrous hydrazine gives racemic pyrazolidinone (78). It appears that py-razolidinone (78) or one of the intermediates suffers base-catalyzed racemization (equation 32). Starting from P-lactam (79) seven-membered cyclic hydrazine (80) has been formed by ring closure in an unusually high (84%) yield (equation 33). Reaction of ( ir-allyl)palladium complex (81) with dimethyl-hydrazine produces exocyclic diene (82) in a modest (29%) yield, but this is still more efficient than the reaction of 2,3-bis(chloromethyl)butadiene (83) with dimethylhydrazine (equation 34). ... 

General aspects 42.4.12 Carbonyl derivatives as dienophiles 4.2.4.1.3 Carbonyl derivatives as dienes... 

The Dewar-benzene iron carbonyl derivative [97], like perfluorobicyclo[2,2,0]hexa-2,5-diene itself, undergoes Diels-Alder addition to give [98a and b], with the chemical shifts shown. (53) [98a] is also formed, although in low yield, by the reaction of the preformed Diels-Alder adduct [99] with Na[(7r-C5H5)Fe(CO)2], confirming the stereochemistry of the addition. 

The protonated form of Fp can add to conjugated carbonyl derivatives such as acrylonitrile596 and also with conjugated dienes.597 Both S03598 and carbon monoxide can be inserted into the Fe—C bond of FpR.598 Protonolysis provides a synthetic route to substituted nitriles or alkenes. In each case the Fp unit can also be removed photochemically, thermally, or by treatment with triphenylphosphine. Hydride extraction to give an alkene or a diene is also known.599... 

Disubstituted quinolines of type 21 were obtained from acetylenic ketones 2 as a result of a condensation reaction with 2-amino thiophenol 19 followed by sulfur extrusion (entry f). Acetylenic ketones have also been employed as dienophiles in Carbonyl-Alkyne-Exchange (CAE) reactions with dienes 22 (derived from 2,2-dialkyl-2,3-dihydro-4//-pyran-4-ones )(entry g) or 24 (entry h) to yield aromatic compounds 23 and 25 in a highly regioselective way. 

If a t(diene)RUCI2In derivative is substituted for ruthenium(III) chloride in this reaction, the reductive carbonylation with zinc to give Rug (CO) 12 pi o-ceeds in reasonable yield, even at atmospheric pressure (252). The increased availability of Rug(CO)12... 

Just as conjugated dienes undergo addition reactions with HX or X2, conjugated carbonyl derivatives also react. The presence of the carbonyl makes the reaction follow a somewhat different path from the dienes, however. A simple conjugated ketone—but-3-en-2-one (methyl vinyl ketone, 10)— illustrates the difference. When an a,[3-unsaturated ketone such as 10 reacts with HCl, the most basic unit in the molecule is the oxygen, not the C=C unit. Therefore, the carbonyl oxygen reacts with H+ to generate 37A. 

Conjugated dienes are molecules that contain two C=C units connected together such that there is a continuous array of sp carbons (C=C-C=C). Conjugate carbonyl compounds have a C=C unit directly attached to the carbon of a carbonyl (C=C-C=0). There are conjugated ketones, aldehydes, acids, and acid derivatives. When a C=C or a C=0 unit is attached to a benzene ring, these are also coqjugated alkenes or carbonyl derivatives 1, 2, 5, 6, 7, 8, 9,10,11,12,13,14, 40, 43. 

An amine is a monofunctional compound. Chapter 24 discusses difunctional compounds, such as dienes, and conjugated carbonyl derivatives. In this section, amino acids are introduced as another class of difunctional compounds with an amine unit and a carboxyl unit in the same molecule. 

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