Copper-catalyzed carbonylations

The potential of aminosulfoximines 85 to be used as ligands in copper-catalyzed carbonyl-ene reactions was also examined [73, 74]. Interestingly, in this case, unsymmetrically substituted 95 gave the best results (up to 91% ee for the synthesis of 94 with R = Me Scheme 2.1.1.32) [75]. 

In 2008, Bhanage and coworkers [50a] reported on a copper-catalyzed carbonylative Sonogashira reaction of aryl iodides. In this procedure, copper bis(2,2,6,6-tetramethyl-3,5-heptanedionate) [Cu(TMHD)2 was used as the catalyst for this transformation and NEtj as base. Alkynones were produced in good yields. Recently, Xia and coworkers [50b] described a general and efficient copper-catalyzed... 

Scheme 5.33 Copper-catalyzed carbonylative Sonogashira reaction...

Copper-catalyzed carbonylative coupling of ( )-a-(ethylsdanyl)-vinyl zircono-cene chloride derivatives with alkynyliodonium tosylates has been reported to be a mild method for the preparation of vinyl alkynyl ketones in good yields (Scheme 12.30) [39]. 

CO, and methanol react in the first step in the presence of cobalt carbonyl catalyst and pyridine [110-86-1] to produce methyl pentenoates. A similar second step, but at lower pressure and higher temperature with rhodium catalyst, produces dimethyl adipate [627-93-0]. This is then hydrolyzed to give adipic acid and methanol (135), which is recovered for recycle. Many variations to this basic process exist. Examples are ARCO s palladium/copper-catalyzed oxycarbonylation process (136—138), and Monsanto s palladium and quinone [106-51-4] process, which uses oxygen to reoxidize the by-product... 

Intramolecular carbonyl ylide formation was also invoked to explain the formation of the AH-1,3-oxazin-5(6//)-ones 291a, b upon copper-catalyzed decomposition of diazoketones 290a, b 270 >. Oxapenam 292, obtained from 290b as a minor product, originates from an intermediary attack of the carbenic carbon at the sulfur atom. In fact, this pathway is followed exclusively if the C(Me, COOMe) group in 290b is replaced by a CH2 function (see Sect. 7.2). 

No specific recommendations can be given about the optimum reaction time. As speeding up reactions is a key motive for employing microwave irradiation, the reaction should be expected to reach completion within a few minutes. On the other hand, a reaction should be run until full conversion of the substrates is achieved. In general, if a microwave reaction under sealed-vessel conditions is not completed within 60 min then it needs further reviewing of the reaction conditions (solvent, catalyst, molar ratios). The reported record for the longest microwave-mediated reaction is 22 h for a copper-catalyzed N-arylation (see Scheme 6.63). The shortest ever published microwave reaction requires a microwave pulse of 6 s to reach completion (ultra-fast carbonylation chemistry see Scheme 6.49). 

Meanwhile, Wacker Chemie developed the palladium-copper-catalyzed oxidative hydration of ethylene to acetaldehyde. In 1965 BASF described a high-pressure process for the carbonylation of methanol to acetic acid using an iodide-promoted cobalt catalyst (/, 2), and then in 1968, Paulik and Roth of Monsanto Company announced the discovery of a low-pressure carbonylation of methanol using an iodide-promoted rhodium or iridium catalyst (J). In 1970 Monsanto started up a large plant based on the rhodium catalyst. 

Palladium catalysts, 10 42 14 49 16 250 Palladium-catalyzed carbonylation, 13 656 Palladium chloride/copper chloride, supported catalyst, 5 329 Palladium compounds, 19 650-654 synthesis of, 19 652 uses for, 19 653-654 Palladium films, 19 654 Palladium membranes, 15 813 Palladium monoxide, 19 651 Palladium oxide, 19 601... 

COPPER-CATALYZED CONJUGATE ADDITION OF ORGANOMANGANESE CHLORIDES, RMnCI, TO ot.p UNSATURATED CARBONYL SUBSTRATES IN THF... 

A copper-catalyzed reaction using a chiral diphosphine hgand, DuPHOS, with an added lanthanide salt, provides good levels of enantioselectivity (67-91% ee) in additions of the simple allylboronate 31 to both aromatic and aliphatic ketones that present a large difference of steric bulk on the two sides of the carbonyl group. One such example is shown in Eq. 81. On the basis of B NMR experiments and on the lack of diastereoselectivity in crotylation reactions, the... 

The synthesis of succinic acid derivatives, /3-alkoxy esters, and a,j3-unsaturated esters from olefins by palladium catalyzed carbonylation reactions in alcohol have been reported (24, 25, 26, 27), but full experimental details of the syntheses are incomplete and in most cases the yields of yS-alkoxy ester and diester products are low. A similar reaction employing stoichiometric amounts of palladium (II) has also been reported (28). In order to explore the scope of this reaction for the syntheses of yS-alkoxy esters and succinic acid derivatives, representative cyclic and acyclic olefins were carbonylated under these same conditions (Table I). The reactions were carried out in methanol at room temperature using catalytic amounts of palladium (II) chloride and stoichiometric amounts of copper (II) chloride under 2 atm of carbon monoxide. The methoxypalladation reaction of 1-pentene affords a good conversion (55% ) of olefin to methyl 3-methoxyhexanoate, the product of Markov-nikov addition. In the carbonylation of other 1-olefins, f3-methoxy methyl esters were obtained in high yields however, substitution of a methyl group on the double bond reduced the yield of ester markedly. For example, the carbonylation of 2-methyl-l-butene afforded < 10% yield of methyl 3-methyl-3-methoxypentanoate. This suggests that unsubstituted 1-olefins may be preferentially carbonylated in the presence of substituted 1-olefins or internal olefins. The reactivities of the olefins fall in the order RCH =CHo ]> ci -RCH=CHR > trans-RCH =CHR >... 

The results show that a number of ruthenium carbonyl complexes are effective for the catalytic carbonylation of secondary cyclic amines at mild conditions. Exclusive formation of N-formylamines occurs, and no isocyanates or coupling products such as ureas or oxamides have been detected. Noncyclic secondary and primary amines and pyridine (a tertiary amine) are not effectively carbonylated. There appears to be a general increase in the reactivity of the amines with increasing basicity (20) pyrrolidine (pKa at 25°C = 11.27 > piperidine (11.12) > hexa-methyleneimine (11.07) > morpholine (8.39). Brackman (13) has stressed the importance of high basicity and the stereochemistry of the amines showing high reactivity in copper-catalyzed systems. The latter factor manifests itself in the reluctance of the amines to occupy more than two coordination sites on the cupric ion. In some of the hydridocar-bonyl systems, low activity must also result in part from the low catalyst solubility (Table I). 

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