Aminocarbonylations of alkynes

The aminocarbonylation of alkynes has been less explored as compared to that of alkenyl and (hetero)aryl halides. Nevertheless, several noteworthy applications of this reaction have been reported, including the syntheses of 2-ynamides, chiral 2-carbamoyl-7r-allylic tungsten complexes, angular triquinanes, 2-(carbamoylmethylene)tetrahydrofurans, alle-nyl amides, and others. ... 

As Scheme 44 exemplifies, the radical intramolecular aminocarbonylation of alkynes 326 and 327 and an azaenyne 328 afforded the corresponding Q-methylene lactams (329, 330 and 331, respectively) in moderate to good yields.i i "... 

Palladium-catalyzed aminocarbonylation of alkynes followed by cyclization produced furans with different substitution pattern in good yields <07S4247>. 

The palladium-catalyzed aminocarbonylation of alkynes proceeds efficiently in BMI-NTf2 IL [95]. The IL acts as the reaction medium and additive because improved product yields and regioselectivities are obtained compared to conventional solvents, without the need of any add additive (Scheme 6.13). 2-Substituted acrylamides are obtained using Pd(OAc)2/dppp as the catalyst in BMI NTf2, whereas only traces of the carbonylation product were detected in THF, DMF, or BMI BF4 IL. 

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

Radical carbonylation reaction serves as a powerful tool for the synthesis of a range of carbonyl compounds. Radical carbonylation has been successfully applied to the synthesis of functionalized ketones from alkyl, aryl, and alkenyl halides.The radical aminocarbonylation reaction of alkynes and azaenynes provided efficient routes to 2-substituted acrylamides, lactams, and pyrrolidinones. For example, the aminocarbonylation of 4-pentyn-l-yl acetate 318 initiated by tributyltin hydride (Bu"3SnH) (30mol%) with AIBN (20mol%) gave acrylamide 325 in 92% yield (Scheme 43).A proposed mechanism starts from the addition of tributyltin radical 319 to alkyne... 

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). 

In the presence of a nickel catalyst, aroyl-, alkanoyl, and aminocarbonyl-stannanes add to alkynes to give (3-acylvinylstannanes (Scheme 5.7.12). " Compared with other nickel-catalyzed carbostannylations of alkynes, the regioselectivity of the acylstannylation is not sufficient. The aminocarbonylstannylation of alkynes is also catalyzed by a rhodium complex. ... 

The palladium-catalyzed aminocarbonylation of alkyl-substituted terminal alkynes with aniline affords either the branched or linear acrylamide, depending on the catalyst composition and reaction conditions [55]. Optimum conditions for the production of the branched unsaturated amide were identified as Pd(OAc)2/dppp/TsOH in THF,... 

Oxidative Hydroxy-, Alkoxy-, and Aminocarbonylation of Terminal Alkynes... 

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... 

Aminocarbonylation has been combined with the Pauson-Khand reaction to construct fused tricyclic alkaloid skeletons (see 00154). The tandem aminocarbonylation/Pauson-Khand reaction of haloalkynes with a chiral allylic amine promoted by Co2(CO)8 gave angular triquinanes as exemplified in Scheme 25. Thus, the reaction of l-chloro-2-phenylethyne 175 with Co2(CO)8 at 0°C gave alkyne-dicobalt complex 176, which was converted to enoyl-dicobalt complex 177 upon warming to 25 °C. The reaction of enoyl-dicobalt complex 177 with cyclopente-nylmethyl(l-phenylethyl)amine 179 yielded Pauson-Khand reaction product, angular triquinane 180, via A -allylic aminocarbonylated alkyne-dicobalt complex 178 (Scheme 25). ... 

The palladium] 11)-catalyzed alkoxy/aminocarbonylation reactions of alkenes and alkynes bearing a tethered nucleophile, usually oxygen or nitrogen nucleophiles, give rise to heterocyclic compounds and follow the mechanisms shown in Scheme 13.43. 

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