“…The transition-metal-catalyzed carbonylation of haloarenes is an efficient and simple method for the synthesis of various aromatic carbonyl compounds, such as aldehydes, ketones, carboxylic acids, esters, amides, benzolactams, lactones, etc. [43][44][45][46] Both bromoand especially iodoarenes can be easily involved in this wide range of diverse transformations, which afford valuable carbonyl compounds in very high yields and excellent selectivities. Unfortunately, chloroarenes are far less reactive toward the iron, cobalt, nickel, and palladium complexes which are commonly used for the carbonylation reactions of aryl iodides and bromides.…”
Section: Carbonylation Of Chloroarenesmentioning
confidence: 99%
“…Unfortunately, chloroarenes are far less reactive toward the iron, cobalt, nickel, and palladium complexes which are commonly used for the carbonylation reactions of aryl iodides and bromides. [43][44][45][46] Considering the availability of chloroaromatics on an industrial scale, the design and development of new catalytic systems for the carbonylation of aryl chlorides remains one of the most important and challenging problems of modern synthetic organic chemistry.…”
“…The transition-metal-catalyzed carbonylation of haloarenes is an efficient and simple method for the synthesis of various aromatic carbonyl compounds, such as aldehydes, ketones, carboxylic acids, esters, amides, benzolactams, lactones, etc. [43][44][45][46] Both bromoand especially iodoarenes can be easily involved in this wide range of diverse transformations, which afford valuable carbonyl compounds in very high yields and excellent selectivities. Unfortunately, chloroarenes are far less reactive toward the iron, cobalt, nickel, and palladium complexes which are commonly used for the carbonylation reactions of aryl iodides and bromides.…”
Section: Carbonylation Of Chloroarenesmentioning
confidence: 99%
“…Unfortunately, chloroarenes are far less reactive toward the iron, cobalt, nickel, and palladium complexes which are commonly used for the carbonylation reactions of aryl iodides and bromides. [43][44][45][46] Considering the availability of chloroaromatics on an industrial scale, the design and development of new catalytic systems for the carbonylation of aryl chlorides remains one of the most important and challenging problems of modern synthetic organic chemistry.…”
“…A specific class of carbonylation reactions concerns the intramolecular cyclization of unsaturated alcohols and amines, leading to the formation of lactones and lactams. − An attractive strategy is the use of cyclocarbonylation reactions since they can provide access to cyclic compounds which are often difficult to synthesize by other methods. Most of the lactone syntheses by this methodology are concerned with monocyclic five-membered ring lactones by the carbonylation of allylic and homoallylic alcohols. − There are no examples of the selective conversion of 2-allylphenols to lactones. We reasoned that the cyclocarbonylation of 2-allylphenols could result in the efficient syntheses of bicyclic and polycyclic lactones of different ring size.…”
2-Allylphenols react with carbon monoxide and hydrogen in the presence of catalytic quantities of a cationic palladium(II) complex [(PCy 3 ) 2 Pd(H)(H 2 O)] + BF 4 -or palladium acetate and 1,4-bis(diphenylphosphino)butane, affording five-or seven-membered ring lactones (bicyclic, tricyclic, and pentacyclic) as the principal products, often in excellent yields. Use of 2-aminostyrenes as reactants and catalytic quantities of palladium acetate and tricyclohexylphosphine, affords five-membered ring lactams in high yield and selectivity. Bicyclic and tricyclic heterocycles containing six-membered ring lactams can be synthesized from the reaction of 2-allylanilines with CO/ H 2 using the catalytic system Pd(OAc) 2 /PPh 3 , while use of 1,4-bis(diphenylphosphino)butane instead of PPh 3 in the latter process results in the formation of the seven-membered lactams benzazepinones in good yield. The regiochemical control depends on the nature of the palladium catalyst, the relative pressures of the gases, and the solvent.
“…The mechanism of carbon monoxide insertion reactions leading to transition metal acyl complexes has long been investigated due to the importance of generating organic products from a CO feedstock. , Migratory insertion of CO into a transition metal−alkyl bond is rarely a simple equilibrium transformation . A few group IV transition metal complexes have been investigated in which acyl-incorporated CO was in equilibrium with free CO (Scheme ). − A series of Pd CO/olefin copolymerization catalysts with methyl and carbonyl ligands underwent reversible migratory insertion, and the acyl intermediate was trapped by addition of CO (Scheme ). , These insightful studies have clarified the details of CO migratory insertion for those systems and thus supplemented definitive investigations of insertion reactions of Mn complexes. − The kinetics and geometry associated with reversible CO migratory insertion in group VI transition metal-alkyl complexes have received less attention. − 3 Reversible Migratory Insertion in Group IV Complexes 4 Reversible CO Migratory Insertion in Pd Complexes…”
Proton addition to the anionic methylene carbene complex [Na][Tp‘(CO)2WCH2] in the
presence of a trapping phosphine ligand generates seven-coordinate complexes of the form
Tp‘(CO)2(PR3)W(CH3) (PR3 = PMe3, PMe2Ph, PMePh2). The seven-coordinate phosphine
complexes are in equilibrium with their CO-insertion products Tp‘(CO)(PR3)W(η2-C(O)Me).
The geometry of these complexes allowed us to probe the stereoselectivity of CO insertion
into the W−Me bond by means of a C-13 spin-saturation transfer NMR experiment. The
ΔG
⧧
358 value determined for the insertion reaction was 18.5 kcal/mol for the PMe2Ph adduct.
Single-crystal structures revealed detailed solid state geometries for Tp‘(CO)2(PMe2Ph)W(CH3), Tp‘(CO)2(PMe3)W(CH3), Tp‘(CO)(PMe3)W(η2-C(O)CH3), and a second isomer of Tp‘(CO)2(PMe3)W(CH3). Trapping of the protonated carbene complex with phenyl acetylene yields
an η1-acyl product.
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