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A concise approach to the synthesis of oxindoles and phenanthridones from anilides is described. In the presence of catalytic amount of Pd(OAc)2, 2-iodoacetates and 2-iodobenzoates can be used to functionalize ortho C-H bond of anilides, which subsequently undergo intramolecular cyclization to give the products. A possible reaction mechanism that involves a PdII/PdIV catalytic cycle is proposed with the support of detailed mechanistic studies. [ABSTRACT FROM AUTHOR]

The ring-opening addition of methyl 2,3-dimethoxy-6-iodobenzoate to oxabenzonorbornadienes followed by cyclization in the presence of NiBr2(dppe) and Zn metal powder in acetonitrile at 80 °C to give the corresponding benzocoumarin derivatives is described. This methodology was then applied to the synthesis of natural product arnottin I, first isolated from Xanthoxylum arnottianum Maxim, using protecting group chemistry. After deprotection and subsequent ring closure, arnottin I was obtained in 21% overall yield after six steps starting from catechol. [ABSTRACT FROM AUTHOR]

An efficient and convenient nickel-catalyzed cyclization of 2-iodoanilines with alkynyl aryl ketones to give 2,4-disubstituted quinolines was developed. The reaction can be employed for the synthesis of naturally occurring quinoline derivatives in good yields. On the basis of the regiochemistry of the products, the possible pathway for the reaction is via the formation of o-aminochalcone. [ABSTRACT FROM AUTHOR]

o-Dihaloarenes acting as aryne precursors react with acetylenes and nitriles catalyzed by the NiBr2(dppe)/dppe/Zn system to give substituted naphthalene, phenanthridine or triphenylene derivatives depending on the reaction conditions in moderate to excellent yields with good tolerance of functional groups. [ABSTRACT FROM AUTHOR]

Investigates the cyclization of iodobenzyl alcohol with alkyl propiolates by nickel complexes. Mechanism for cyclization; Catalysis of intramolecular cyclocarbonylations of 2-allylphenols by Pd complexes; Role of E/Z isomerization of carbon-carbon double bond.

An efficient cobalt-catalyzed carbocylization for the synthesis of indenols and indenes and a new method for reductive decyanation are described. 2-Iodophenyl ketones and aldehydes la-g undergo carbocyclization with various disubstituted alkynes 2a-k in the presence of Co(dppe)I2 and zinc powder in acetonitrile at 80 °C for 3 h to afford the corresponding indenol derivatives 3a-s and 4a-m in good to excellent yields. For some unsymmetrical alkynes, the carbocyclization was remarkably regioselective, affording a single regioisomer. The cobalt-catalyzed carbocyclization reaction was successfully extended to the synthesis of indene derivatives. Thus, the reaction of 2-iodophenyl ketones and aldehydes (1) with acrylates H2C=CHCO2R (7a-d) and acrylonitrile H2C= CHCN (7e) proceeds smoothly in the presence of Co(dppe)Cl2/dppe and zinc powder in acetonitrile at 80 °C for 24 h to afford the corresponding indenes 8a-k and 9a-c in moderate to good yields. Interestingly, when 7e was employed for the carbocylization, reductive decyanation also occurred to give an indene derivative without the cyano functionality. A possible mechanism for this cobalt-catalyzed carbocyclization reaction is also proposed. [ABSTRACT FROM AUTHOR]

2-Halophenyl ketones 1a-e (1a, o-IC[sub 6]H[sub 4]COCH[sub 3]) undergo carbocyclization with alkyl propiolates (2a, CH[sub 3](CH[sub 2])[sub 4]C≡CCO[sub 2]CH[sub 3]; 2b, TMSC≡CCO[sub 2]Et 2c, CH[sub 3]C≡CCO[sub 2]CH[sub 3]; 2d, CH[sub 3]OCH[sub 2]C≡CCO[sub 2]CH[sub 3]; 2e, CH[sub 3](CH[sub 2])[sub 3]C≡CCO[sub 2]CH[sub 3]; 2f, PhC≡CCO[sub 2]CH[sub 3]; and 2g, (CH[sub 3])[sub 3]C≡CCO[sub 2]CH[sub 3]) in the presence of Ni(dppe)Br[sub 2] and zinc powder in acetonitrile at 80 °C to afford the corresponding indenol derivatives 3a-m with remarkable regioselectivity in good to excellent yields. The nickel-catalyzed carbocyclization reaction was successfully extended to other simple disubstituted alkynes. Thus, the reaction of 2-halophenylketones 1a-e with disubstituted alkynes (2h, PhC≡CPh; 2i, CH[sub 3]C[sub 6]H[sub 4]C≡CC[sub 6]H[sub 4]CH[sub 3]; 2j, CH[sub 3]CH[sub 2]C≡CCH[sub 2]CH[sub 3]; 2k, PhC≡CCH[sub 3]; 21, TMSC≡CCH[sub 3]; and 2m, PhC≡C(CH[sub 2])[sub 3]CH[sub 3]) proceeded smoothly to afford the corresponding indenols 4a-t in good to excellent yields. For unsymmetrical alkynes 2k-m, the carbocyclization gave two regioisomers with regioselectivities ranging from 1:2 to 1:12 depending on the substituents on the alkyne and on the aromatic ring of halophenyl ketone. A possible mechanism for this nickel-catalyzed carbocyclization reaction is also proposed. [ABSTRACT FROM AUTHOR]

The article discusses the study on the new method for the synthesis of phenanthrone derivatives from sec-alkyl aryl ketones and aryl iododes catalyzed by palladium acetate in trifluoroacetatic acid. It notes that palladium-catalyzed direct transformations of inactive carbon (C) - hydrogen (H) bonds into various functional groups has emerged as a powerful method in organic synthesis. It cites that the catalytic reaction proceeds via a dual C - H activation and enolate cyclization.

The article provides information related to cobalt-catalyzed diastereoselective reductive cycloaddition of allenes and enones. The cycloaddition reaction is one of the primary methods to construct five-membered carbocycles, which are common structural cores of a large number of biologically important natural products and target molecules for numerous synthetic studies.

A highly regio- and stereoselective nickel-catalyzed three-component coupling of alkynes with enones and alkenyl boronic acids to afford highly substituted 1,3-dienes is described. The reaction can also be extended to cyclization of enynes with coupling to alkenyl boronic acids. A possible reaction mechanism involving a five-membered nickelacycle as a key intermediate is proposed. [ABSTRACT FROM AUTHOR]

Diynes 1a-c [X(CH[sub 2]C≡CCO[sub 2]Me)[sub 2]: X = (CH[sub 2])[sub 2], 1a, X = CH[sub 2], 1b and X = O, 1c] undergo [2 + 2 + 2] ene-diyne cycloaddition reactions with a variety of allenes (n-butylallene 2a, phenylallene 2b, (4-chlorophenyl)allene 2c, (4-bromophenyl)allene 2d, (3-methoxyphenyl)allene 2e, 1-naphthylallene 2f, cyclohexylallene 2g and cyclopentylallene 2h) in the presence of Ni(dppe)Br[sub 2] and Zn powder in CH[sub 3]CN at 80 °C for 8 h to give the corresponding polysubstituted benzene derivatives 4a-l in good to excellent yields. Under similar reaction conditions, unsymmetrical diynes 5a-c (HC≡CCH[sub 2]XCH[sub 2]C≡CCO[sub 2]Me) react with allenes 2 to afford exclusively the corresponding meta-isomers 6a-g in 73-86% yields. The catalytic reaction is highly regioselective and completely chemoselective. This synthetic method is compatible with many functional groups such as Cl, Br, and OMe on the phenyl group of the allene moiety and an ether linkage in a diyne moiety. In this catalytic reaction, allenes are synthetically equivalent to terminal alkynes. Interestingly, unsymmetrical diyne 7 (MeC≡C(CH[sub 2])[sub 4]C≡CCO[sub 2]Me) undergoes 2:1 cocyclotrimerization with allenes 2a and 2g to afford the corresponding polysubstituted benzene derivatives 9a,b in 87% and 82% yields, respectively. A plausible mechanism involving a nickelacycloheptadiene intermediate is proposed to account for this nickel-catalyzed reaction. [ABSTRACT FROM AUTHOR]

Reports on the cross cycloaddition of bicyclic alkenes with alkynes mediated by cobalt complexes. Endo position of protons at the ring junction; Regioisomers for cross cycloaddition of unsymmetrical oxanorbornadienses with unsymmetrical alkynes.