Oxidative aminocarbonylation

The catalytic oxidative carbonylation of allene with PdCb and CuCh in MeOH affords methyl a-methoxymethacrylate (559)[499]. The intramolecular oxidative aminocarbonylation of the 6-aminoallene 560 affords the unsaturated J-amino ester 561. The reaction has been applied to the enantioselective synthesis of pumiliotoxin (562)[500]. A similar intramolecular oxycarbonyla-tion of 6-hydroxyallenes affords 2-(2-tetrahydrofuranyl)acrylates[501]. 

Penta-2,4-dienamides have been obtained by stoichiometric Ni(II)-pro-moted oxidative aminocarbonylation of 1,3-butadiene (Eq. 16) [56]. 

The oxidative aminocarbonylation of terminal alkynes 181 with diethylamine or morpholine led to the formation of... 

Based upon the oxidative aminocarbonylation of terminal alkynes [141], a conjugate addition of the amine to the ynoylamide leads to the stereoselective formation of an -configured 2-amino 3-hydroxy enamide that lactonizes to furnish the dialkylamino-5H-furan-2-one 195 (Scheme 78). 

The palladium(II)-catalyzed oxidative aminocarbonylation of 0-(2-propenyl)-Ar-tosyl carbamates 12 was achieved under acidic buffer conditions, although the reaction was very sluggish, or, preferably in the presence of acetate ion and methyl orthoacetate, which suppresses palladium(II) chloride consuming side reactions114. Substitution at C-l led to the prevalent formation of the trans-4,5-disubstituted 1,3-oxazolidin-2-ones 13 (NMR). 

Chiral 2-oxazolidinones are an important class of heterocycles. These compounds are known for their synthetic utility as chiral auxiliaries and their pharmacological properties, specifically as antimicrobial agents. One of the most synthetically appealing methods for the synthesis of these compounds is the annulation of an acyclic precursor. In 2007, Gabriele and co-workers reported the synthesis of the 2-oxazolidinones 168 from a,a-disubstituted 2-ynylamines 167 using an unprecedented Pd-catalyzed water-promoted sequential oxidative aminocarbonylation-cyclocarbonylation process with secondary amines in the presence of carbon monoxide, oxygen, water, and potassium iodide (KI) (Scheme 78) (140). 

In a similar transformation, oxidative aminocarbonylation of alkyl- and aryl-substituted 1-alkynes is catalyzed by Pdl2/KI under relatively mild conditions to afford 2-ynamides 64 in good yield (Scheme 10.20) [60]. Nucleophilic secondary amines were required as amines of low basicity were unreactive and primary amines gave complex reaction mixtures. The key intermediate in the mono-aminocarbonylation was proposed to be an alkynyl palladium iodide that undergoes CO insertion followed by nucleophilic abstraction by amine to generate the product and Pd(0), which is reoxidized by iodine (2HI + I/2O2 = I2 + H2O). Small amounts of diaminocarbonylation product (maleic... 

Dihydropyrazines are formed by the self-condensation of a-aminocarbonyl compounds and they are relatively stable, although again they are easily oxidized to the corresponding pyrazines. Tetrahydropyrazines are less well documented and structures such as (87) appear to be more stable than the enediamine (88). 

Oxidative cyclization of 1 -[(2 -aminocarbonyl)phenyl]piperidine and its 4 -substituted derivatives with Hg(OAc)2-EDTA reagent afforded 1,2,3,4-tet-rahydro-6//-pyrido[2,l-Z)]quinazolin-6-one and its 3-substituted derivatives in 36-82% yields (99ZN(B)1577). Similarly, ( )-2-(piperidin-2-yl)benzal-doximes gave 2,3,4,4u-tetrahydro-l//-pyrido[l,2-u]quinazolin-5-oxide and... 

Reaction of iV-aminocarbonyl-2-phenylethylamines with mesityl oxide and 2-butenal afforded l,2,3,6,7,llb-hexahydro-477-pyrimido[6,l- ]isoquinoline-4-ones <2003MC278>. 9,10-Dimethoxy-l,2,3,6,7,llb-... 

On the other hand, unsaturated /J-aminoamides have been obtained by Ni(II)-promoted stoichiometric oxidative amino-aminocarbonylation of substituted allenes [60] (Eq. 19). 

T. Komano worked with him. The work accomplished at that time included the following N-debenzyloxycarbonylation of 1,3,4,6-tetra-0-acetyl-2-(benzyloxycarbonyl)amino-2-deoxy-D-hexopyranoses in the conversion of a,/3-acetoxy to glycosyl bromide (1961) oxidative cleavages of 1,2-diamino sugars and their significance in the mechanism of the aminocarbonyl reactions (1962) and synthesis of 2-amino-2-deoxy-/3-o-glucosides via 3,4,6-tri-D-acetyl-2-benzylsulfonamido-2-deoxy-a-D-glu-copyranosyl bromide (1962). 

In the pyridine V-oxide series a C-N exchange rearrangement was also observed when 3-aminocarbonyl-l-methoxypyridinium salt (131) reacts with ammonia or alkali, 3-methoxyiminomethylpyridin-2(l//)-one (132) being obtained (74T4055). This conversion takes place via the ANRORC pathway the ring opening occurs between N-1 and C-6 after initial addition of the hydroxide ion at C-6 (Scheme IV.50). 

Tab. 51 2,5-disubst. 1,3,4-Oxadiazole durch Oxidation von Aidehyd-[aroyl(hetaroyl)-hydra-zonen] bzw. -(aminocarbonyl-hydrazonen) mit Brom bzw. Iod/Kaliumiodid... 

Fur die Synthese von 2,5-Diaryl(Dihetaryl)- bzw. 2-Amino-l,3,4-oxadiazolen durch oxidative Cyclisierung von 2-Acyl- bzw. 2-Aminocarbonyl-hydrazonen aromatischer und he-terocyclischcr Aldehyde ist ebenfalls Blei(IV)-acetat erfolgreich eingesetzt worden495 498 die Reaktion verlauft liber Nitrilimine als 1,5-Elektrocyclisierung504. 

Beim Kochen einer waBr. Losung von 3,4-Bis-faminocarbonyl]-furazan-2-oxid wird u.a. 4-Amino-3-aminocarbonyl-furazan erhalten221,222. Die Reaktion verlauft vermutlich nach folgen-dem Mechanismus ab (vgl.a. S. 654) ... 

Since formamide is a weak nucleophile, the use of imidazole or 4-dimethylaminopyridine (DMAP) is necessary for acyl transfer to formamide via an activated amide (imidazolide) or acylpyridinium ion. As Scheme 22 illustrates, the reaction starts with the oxidative addition of aryl bromide 152 to Pd(0) species, followed by CO insertion to form acyl-Pd complex 154. Imidazole receives the aroyl group to form imidazolide 155 and liberates HPdBr species. Then, imidazolide 155 reacts with formamide to form imide 156. Finally, decarbonylation of imide 156 gives amide 157. In fact, the formations of imidazolide intermediate 155 and imide 156 as well as the subsequent slow transformation of imide 156 to amide 157 by releasing CO were observed. This mechanism can accommodate the CO pressure variations observed during the first few hours of aminocarbonylation. When the reaction temperature (120 °C) was reached, a fast drop of pressure occurred. This corresponds to the formation of the intermediary imide 156. Then, the increase of pressure after 3 h of reaction was observed. This phenomenon corresponds to the release of CO from imide 156 to form amide 157. ... 

When the bulky t-butyl group is present at the ring nitrogen of 3-aminocarbonylpyridine, oxidative amination occurs at C-4, yielding 3-aminocarbonyl-1 -t-butyl-4-imino-1,4-dihydropyridine (Scheme 37). No imination was observed at C-6, although NMR spectroscopy of a solution of 3-aminocarbonyl-1-t-butylpyridinium iodide clearly shows the presence of two adducts, one adduct at C-4, the other one at C-6 (ratio 4 6). 

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