Photochemical Ring Enlargements of Two α-Cyanocycloalkanones

Chip, G. K.; Lynch, Thomas R.

doi:10.1139/v74-325

Cited by 8 publications

(1 citation statement)

References 9 publications

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“…These heterocycles are the expected products from a CO insertion/C–N reductive coupling sequence. Only a few nine-membered cyclic imides have been previously reported, which were synthesized via ring expansion reactions or oxidation of nine-membered lactams . Under the same reaction conditions, complex 12a , containing inserted dimethylacetylenedicarboxylate (DMAD), was recovered unreacted, probably because the low nucleophilicity of the vinylic carbon bonded to palladium hampers the CO insertion step.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Reactivity of Ortho-Palladated 3-Phenylpropanamides. Insertion of CO, XyNC, and Alkynes into the Pd–C Bond. Synthesis of Seven- and Nine-Membered Palladacycles and Benzazepine- and Benzazonine-Based Heterocycles

et al. 2013

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Aryl palladium complexes [Pd{C 6 H 4 (CH 2 ) 2 C(O)-NRR′)-2}I(tmeda)] [NRR′ = NH 2 (1a), NHMe (1b), NMe 2 (1c); tmeda = N,N,N′,N′-tetramethylethylenediamine] are prepared by oxidative addition of the corresponding 3-(2iodophenyl)propanamides to "Pd(dba) 2 " ([Pd 2 (dba) 3 ]•dba; dba = dibenzylideneacetone) in the presence of tmeda. The cationic seven-membered palladacycles [Pd{κ 2 C,O-C 6 H 4 (CH 2 ) 2 C(O)-NRR′)-2}(tmeda)]TfO (2a−c) are obtained by reacting 1a−c with AgTfO. Neutral amidate complexes of the type [Pd{κ 2 C,N-C 6 H 4 (CH 2 ) 2 C(O)NR)-2}(tmeda)] [R = H (3a), Me (3b)] are obtained upon deprotonation of the amide function in 1a or 1b with KO t Bu. The reaction of 1a with CO at room temperature affords the stable acyl derivative [Pd{C(O)C 6 H 4 (CH 2 ) 2 C-(O)NH 2 -2}I(tmeda)] (4), while 2a gives Pd, (tmedaH)TfO, and 4,5-dihydro-2H-benzo[c]azepine-1,3-dione (5a). Compound 5a can also be obtained in high yield by treating the amidate complex 3a with CO, while a low yield of 2-methyl-4,5-dihydro-2Hbenzo[c]azepine-1,3-dione (5b) was obtained from 3b under the same conditions. Complexes 1a−c react with 3 equiv of XyNC to give trans-[Pd{C(NXy)C 6 H 4 (CH 2 ) 2 C(O)NRR′-2}I(CNXy) 2 ] [NRR′ = NH 2 (6a), NHMe (6b), NMe 2 (6c)]. By refluxing a CHCl 3 solution of 6a or 1a and XyNC in 1:1 molar ratio, mixtures of 1-(2,6-dimethylphenylimino)-1,2,4,5tetrahydrobenzo[c]azepin-3-one (7a) and 2-(2-cyanoethyl)-N-(2,6-dimethylphenyl)benzamide (8a) are obtained. Complexes 2a−c react with alkynes in 1:1 molar ratio to give nine-membered palladacycles of the type [Pd{κ 2 C,O-C(X) C(X)C 6 H 4 (CH 2 ) 2 C(O)NRR′-2}(tmeda)]TfO [NRR′ = NH 2 , X = Ph (9a), C 6 H 4 n Bu-4 (10a), C 6 H 4 Br-4 (11a), CO 2 Me (12a); NRR′ = NHMe, X = Ph (9b); NRR′ = NMe 2 , X = Ph (9c)]. The reaction of 2a with an excess of 3-hexyne gives the complex [Pd{η 3 -C 6 H 4 (C 4 Et 4 )(CH 2 ) 2 C(O)NH 2 }(tmeda)]TfO (13), containing a spirocyclic ligand coordinated to Pd through a η 3 -allylic bond. The derivatives 9a, 10a and 11a react with CO at 50 °C in CHCl 3 to give colloidal Pd, (tmedaH)TfO, and the corresponding 6,7-disubstituted 1,2-dihydro-4H-benzo[e]azonine-3,5-diones (14, 15, 16), which result from a CO insertion/C− N reductive coupling sequence.

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Section: Resultsmentioning

confidence: 99%