Palladium-Catalyzed Intermolecular Cyclocarbonylation of 2-Iodoanilines with the Michael Acceptor, Diethyl Ethoxycarbonylbutendienoate

Abstract

Palladium-catalyzed intermolecular cyclocarbonylation of 2-iodoanilines with diethyl ethoxycarbonylbutendienoate produces 2,3,3-triethoxycarbonyl-2,3-dihydro-4(1H)-quinolinone derivatives in moderate to good yields. This protocol involves Michael addition and subsequent carbonylation.

Palladium-Catalysed Synthesis and Transformation of Quinolones

“…Highly functionalized 2,3-dihydroquinolin-4(1 H )-ones 173 were obtained in one step, with moderate to good yields, by Pd-catalysed intermolecular cyclocarbonylation of 2-iodoanilines 1 with diethyl ethoxycarbonylbutendienoate 172 (Scheme 56) [78]. The method involves a Michael addition and subsequent carbonylation reactions using the catalytic system of Pd 2 (dba) 3 /2-(di- t -butylphosphino)biphenyl in MeCN at 80 °C under 500 psi of CO.…”

“…Formation of 175 was explained by intermolecular double carbonylation of 1 with 174 formed in situ. First intermolecular carbonylation takes place between 1 and 174 affording an acyclic amide II and/or III, which can then undergo a second intramolecular carbonylation to give the final product 175 (Scheme 57) [78].…”

Palladium-Catalyzed Carbonylative Synthesis of Six-Membered Heterocycles from Aryl Halides

“…A palladium-catalyzed carbonylation-decarboxylation process may be involved in the one-step synthesis of the isoquinolin-1(2H)-ones. Later on, Okuro and Alper reported a palladium-catalyzed intermolecular cyclocarbonylation of 2-iodoanilines with diethyl ethoxycarbonylbutendienoate [74]. By the similar procedure involving Michael addition and subsequent carbonylation, 2,3,3-triethoxycarbonyl-2,3-dihydro-4(1H )-quinolinone derivatives were obtained in moderate to good yields (Scheme 44).…”

Palladium-Catalyzed Synthesis of 1,2,3,4-Tetrahydro-5H-2-benzazepin-5-ones

“…These results are in sharp contrast with those of 2-iodoanilines, where 2b and 2c were not successfully used. 5 When diethyl benzylidenemalonate (2d) was used as a Michael acceptor, the reaction proceeded to some extent at 100 °C, but the yield of the expected product 3ad was unsatisfactory (entry 12). In this olefin, increasing temperature to 120 °C did not improve the yield (9%).…”

“…A possible reaction mechanism for the formation of 3 consists of the following steps (Scheme 2): 5 (1) aza-Michael 1a: R 1 = R 2 = R 3 = R 4 = H 1b: R 1 = R 3 = R 4 = H, R 2 = Cl 1c: R 1 = R 2 = R 4 = H, R 3 = Cl 1d: R 1 = R 2 = R 4 = H, R 3 = Me 1e: R 1 = OMe, R 2 = R 3 = R 4 = H 1f: R 1 = R 2 = R 3 = H, R 4 = OMe 1g: R 1 = R 2 = R 3 = H, R 4 = F addition of 1 to 2 to form the Michael adduct, (2) oxidative addition of Pd(0) to the C-I bond of the adduct, 8 (3) insertion of carbon monoxide into the Pd-C bond to form aroylpalladium species, and (4) nucleophilic attack of the internal malonate anion on the aroylpalladium intermediate to give the product 3 and regeneration of Pd(0) species. 9 One of the crucial steps for the successful reaction is the initial aza-Michael addition.…”