Amine carbonylation catalyzed

Amine Carbonylation Catalyzed by Ruthenium Complexes under Mild Conditions... 

Most ring syntheses of this type are of modern origin. The cobalt or rhodium carbonyl catalyzed hydrocarboxylation of unsaturated alcohols, amines or amides provides access to tetrahydrofuranones, pyrrolidones or succinimides, although appreciable amounts of the corresponding six-membered heterocycle may also be formed (Scheme 55a) (73JOM(47)28l). Hydrocarboxylation of 4-pentyn-2-ol with nickel carbonyl yields 3-methylenetetrahy-drofuranone (Scheme 55b). Carbonylation of Schiff bases yields 2-arylphthalimidines (Scheme 55c). The hydroformylation of o-nitrostyrene, subsequent reduction of the nitro group and cyclization leads to the formation of skatole (Scheme 55d) (81CC82). 

Ethers, sulfides, amines, carbonyl compounds, and imines are among the frequently encountered Lewis bases in the ylide formation from such metal carbene complex. The metal carbene in the ylide formation can be divided into stable Fisher carbene complex and unstable reactive metal carbene intermediates. The reaction of the former is thus stoichiometric and the latter is usually a transition metal complex-catalyzed reaction of a-diazocarbonyl compounds. The decomposition of a-diazocarbonyl compounds with catalytic transition metal complex has been the most widely used approach to generate reactive metal carbenes. For compressive reviews, see Refs 1,1a. 

The ruthenium carbonyl complexes [Ru(CO)2(OCOCH3)] n, Ru3(CO)12, and a new one, tentatively formulated [HRu-(CO)s ] n, homogeneously catalyze the carbonylation of cyclic secondary amines under mild conditions (1 atm, 75°C) to give exclusively the N-formyl products. The acetate polymer dissolves in amines to give [Ru(CO)2(OCOCH3)(amine)]2 dimers. Kinetic studies on piperidine carbonylation catalyzed by the acetate polymer (in neat amine) and the iiydride polymer (in toluene-amine solutions) indicate that a monomeric tricarbonyl species is involved in the mechanism in each case. 

Kinetic studies on catalytic amine carbonylation reactions are scarce, although Brackman (13) has reported kinetics on a copper(I)-copper(II) catalyzed production of ureas from cyclic secondary amines using carbon monoxide-oxygen mixtures at ambient conditions. Saegusa and coworkers (14) used cuprous salts and other group IB and IIB metal compounds to car bony late piperidine to N-formylpiperidine under more severe conditions. We have published (15) a brief report involving some of the studies described in this paper. 

Metal carbonyls, particularly cobalt carbonyl, catalyze the carbonylation of primary amines to formamides and ureas 113, 412), and for many years it was thought that the mechanism involved intermediate carbamoyl... 

The oxidative carbonylation and double carbonylation of amines is catalyzed by PdCl2/CuCl2 in the presence of acid and Bu OOBu as oxidizing agent at room temperature see equation (58). Bulky amines give good yields of double-carbonyla-tion products.In a related system, piperidine is doubly carbonylated to ox-amates in the presence of a [PdCl2(MeCN)2]/CuI catalyst, O2 as the oxidant and... 

Ruthenium dihydride complex [Ru(H)2(CO)(PPh3)3], activated by treatment with st3rrene, catalyzes several hydrosilylation polymerization processes, such as the reaction of tereftaldehyde with 1,3-tetramethyldisiloxane and hydrosilylation of poly(l-hydrido-l,3,3,5,5-pentamethyltrisiloxane) with benzophenone (221,222). [Ru3(CO)i2] was found catalytically active in the hydrosilylation of acetophenone with HSi(OEt)3 (222). The same cluster and several ruthenium carbonyl complexes efficiently catalyze the reduction of linear and cyclic amides with trisubstituted silanes to give the corresponding amines (224). Activated diruthenium and triruthenium carbonyls catalyze the hydrosilylation of ketones, as well as that of aldehydes wdth different silanes (225). First-generation Grubbs... 

VI Pd-CATALYZEDCARBONYLATION AND OTHER RELATED REACTIONS TABLE 5. Pd-Catalyzed Cyclic Amination-Carbonylative Lactonization Tandem Reaction... 

Cobalt carbonyl-catalyzed hydrosilylation of aromatic nitriles with HSiMes proceeds smoothly at 60 °C and ambient pressure of carbon monoxide in toluene to give N, Af-bis-TMS-amines 191 in moderate to excellent yields (equation 78) . Reactions of aliphatic nitriles require 100 °C, except for cyclopropanenitrile, to give 191 in 87-100% yields. The reaction of butanenitrile gives a mixture of 191 (R = n-Bu) (44%) and N, Af-bis-TMS-enanime CH3CH2CH=CHN(SiMe3)2 (20%). The reactions of a, yS-unsaturated nitriles bearing substituent(s) at the a- and/or -position(s) give N, Af-bis-TMS-enamines 192 (Z/E mixture) as the major products accompanied by iV, Af-bis-TMS-allylic amines 193 and/or saturated N, Af-bis-TMS-amines 194 (equation 19). ... 

The first amine-catalyzed Diels-Alder reaction of a,(i-unsaturated carbonyl compounds as dienes involving in situ enamine activation with chiral amine 29 through raising the diene HOMO energy was accomplished by Barbas and coworkers in 2002 with moderate enantioselectivity (up to 38% ee) [17a]. In 2007, Cordova and coworkers described chiral amine 29 catalyzed enantioselective Diels-Alder reactions between a,P-unsaturated cyclic ketones and nitroolefins with up to 86% ee [17b]. Two years later, Xu and coworkers successfully disclosed a highly efficient enantioselective Diels-Alder reaction of cyclohexenones 31 with aromatic nitroolefins 32 using amine 30 as catalyst in seawater or brine to give products 32 with excellent enantioselectivities (Scheme 38.10) [18a]. Notably, sea water and brine... 

Ammonia reacts with the ketone carbonyl group to give an mine (C=NH) which is then reduced to the amine function of the a ammo acid Both mine formation and reduc tion are enzyme catalyzed The reduced form of nicotinamide adenine diphosphonu cleotide (NADPH) is a coenzyme and acts as a reducing agent The step m which the mine is reduced is the one m which the chirality center is introduced and gives only L glutamic acid... 

Certain reactions between carbonyl compounds and nucleophiles are catalyzed by amines. Some of these reactions are of importance for forming carbon-carbon bonds, and these are discussed in Chapter 2 of Part B. The mechanistic principle can be illustrated by considering the catalysis of the reaction between aldehydes and hydroxylamine by aniline derivatives. 

High enantioselectivities may be reached using the kinetic controlled Michael addition of achiral tin enolates, prepared in situ, to a,/i-unsaturated carbonyl compounds catalyzed by a chiral amine. The presence of trimethylsilyl trifluoromethanesulfonate as an activator is required in these reactions236. Some typical results, using stoichiometric amounts of chiral amine and various enolates are given below. In the case of the l-(melhylthio)-l-[(trimethylsilyl)thio]ethene it is proposed that metal exchange between the tin(II) trifluoromethanesulfonate and the ketene acetal occurs prior to the 1,4-addition237,395. 

The most widely employed methods for the synthesis of nitrones are the condensation of carbonyl compounds with A-hydroxylamines5 and the oxidation of A+V-di substituted hydroxylamines.5 9 Practical and reliable methods for the oxidation of more easily available secondary amines have become available only recently.10 11 12 13. These include reactions with stoichiometric oxidants not readily available, such as dimethyldioxirane10 or A-phenylsulfonyl-C-phenyloxaziridine,11 and oxidations with hydrogen peroxide catalyzed by Na2W044 12 or Se02.13 All these methods suffer from limitations in scope and substrate tolerance. For example, oxidations with dimethyldioxirane seem to be limited to arylmethanamines and the above mentioned catalytic oxidations have been reported (and we have experienced as well) to give... 

Palladium complexes also catalyze the carbonylation of halides. Aryl (see 13-13), vinylic, benzylic, and allylic halides (especially iodides) can be converted to carboxylic esters with CO, an alcohol or alkoxide, and a palladium complex. Similar reactivity was reported with vinyl triflates. Use of an amine instead of the alcohol or alkoxide leads to an amide. Reaction with an amine, AJBN, CO, and a tetraalkyltin catalyst also leads to an amide. Similar reaction with an alcohol, under Xe irradiation, leads to the ester. Benzylic and allylic halides were converted to carboxylic acids electrocatalytically, with CO and a cobalt imine complex. Vinylic halides were similarly converted with CO and nickel cyanide, under phase-transfer conditions. ... 

In a similar way, lipases catalyze Michael addition of amines, thiols [110], and even 1,3-dicarbonyl derivatives [111, 112] to a,/ -unsaturated carbonyl compounds (Scheme 5.21). 

The direct reductive amination (DRA) is a useful method for the synthesis of amino derivatives from carbonyl compounds, amines, and H2. Precious-metal (Ru [130-132], Rh [133-137], Ir [138-142], Pd [143]) catalyzed reactions are well known to date. The first Fe-catalyzed DRA reaction was reported by Bhanage and coworkers in 2008 (Scheme 42) [144]. Although the reaction conditions are not mild (high temperature, moderate H2 pressure), the hydrogenation of imines and/or enam-ines, which are generated by reaction of organic carbonyl compounds with amines, produces various substituted aryl and/or alkyl amines. A dihydrogen or dihydride iron complex was proposed as a reactive intermediate within the catalytic cycle. 

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