Ruthenium-catalyzed oxidative annulation of N-quinolin-8-yl-benzamides with alkynes in open air has been achieved using 8-aminoquinolinyl moiety as a bidentate directing group the presence Cu(OAc)2·H2O an oxidant. This reaction offers broad substrate scope, and both symmetrical unsymmetrical can be applied. High regioselectivity was case (aryl)alkynes. Reaction heteroaryl amides also successful this catalytic process. A ruthenium-N-quinolin-8-yl-benzamide complex isolated absence alkyne;...

A novel and efficient [Cu]-catalyzed one-pot regio- stereospecific synthesis of benzo[1,4,2]dithiazine 1,1-dioxides benzo[1,4,2]thiaselenazine by cyclization functionalized ynamides with elemental sulfur/selenium has been developed. Its generality is elegantly illustrated extension to benzodithiazepines benzothiaselenazepines. Involvement water in the reaction demonstrated incorporation (2)D at olefinic site using D2O place water. Selective oxidation sulfur 1,1-dioxide mCPBA as oxidizing...

Coupling reactions of allenylphosphonates (OCH2CMe2CH2O)P(O)CHCCRR' [R, R' = H (1a), R H, Me (1b), (1c)] with aryl iodides, iodophenol, and iodobenzoic acid in the presence palladium(II) acetate are investigated compared those phenylallenes PhCHCCR2 [R (2a), (2b)] allenyl esters EtO2CCHCCR2 (2c), (2d)]. While 1b 1c couple different stereochemical outcomes using PhI Pd(OAc)2/PPh3/K2CO3 to give phenyl-substituted 1,3-butadienes, 1a does not undergo coupling but isomerizes acetylene...

Two methodologies, one involving Ar–I reactivity and the other through C–H functionalization, for formation of indolo[2,3-c]pyrane-1-ones via corresponding allenes, are presented. A highly efficient approach to indolo[2,3-c]pyrane-1-one derivatives Pd-catalyzed regioselective annulation allenes with 3-iodo-1-alkylindole-2-carboxylic acids is described. This method fairly general a wide range affording respective in good excellent yields. In addition, Pd(II)-catalyzed oxidative coupling...

Regioselective synthesis of functionalized dihydropyran derivatives by DABCO-catalyzed [2 + 4] cycloaddition allenoates with enynals or enynones has been developed. Phosphine-catalyzed [3 2] provides 1,1-alkyne (aldehyde)-substituted cyclopentenes wherein act as electrophiles. These alkyne-tethered upon [Au]/[Ag] catalysis lead to substituted benzofurans via 1,2-alkyl migration and dehydrogenation (aromatization). One-pot reaction using sequential phosphine gold is also reported. The...

Abstract Ethanol is shown to act as a hydrogenating agent for ynamides under palladium catalysis. This behavior different from the normally expected reaction of ethanol addition alkynes. The shows stereoselectivity E enamides, which in contrast reports using other sources. method was also extended ynamines. Alternatively, use and ammonium formate source gives Z enamides. role hydrogenation demonstrated by means deuterium labeling experiment.

Utilizing internally available functional groups, a simple protocol for the efficient synthesis of phosphorus-based indenes, indenones, benzofurans, and isochromenes via intramolecular cyclization allene intermediates/precursors is generated; latter are conveniently obtained through aldehyde-, alkylidene-, hydroxyl-functionalized propargyl alcohols P(III)-Cl precursors. The structures key products have been unequivocally confirmed by X-ray crystallography.

The reactivity of 2-sulfonamidoindoles with acetoxy allenoates under phosphine catalysis depends on the disposition (OAc) group allenoate. In temperature-controlled [3 + 3] annulations, δ-acetoxy afforded dihydrocarboline and carboline scaffolds carbon–nitrogen nucleophilic 2-sulfonamidoindoles, in which allenoate serves as a β-, γ-, δ-carbon donor. At room temperature (25 °C), dihydro-α-carboline motifs were obtained exclusively through Michael addition, 1,4-proton shift, isomerization,...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPentacoordinated molecules. 79. Pentacoordinate acyclic and cyclic anionic oxysilicates. A silicon-29 NMR x-ray structural studyK. C. Kumara Swamy, V. Chandrasekhar, John J. Harland, Joan M. Holmes, Roberta O. Day, Robert R. HolmesCite this: Am. Chem. Soc. 1990, 112, 6, 2341–2348Publication Date (Print):March 1, 1990Publication History Published online1 May 2002Published inissue 1 March...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOrganotin clusters. 4. Cubic, butterfly, and oxygen-capped clusters of n-butyloxotin phosphinates. A new class organotin compoundsRobert R. Holmes, K. C. Kumara. Swamy, Charles G. Schmid, Roberta O. DayCite this: J. Am. Chem. Soc. 1988, 110, 21, 7060–7066Publication Date (Print):October 1, 1988Publication History Published online1 May 2002Published inissue 1 October...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA new structural form of tin in a cubic clusterK. C. Kumara Swamy, Roberta O. Day, and Robert R. HolmesCite this: J. Am. Chem. Soc. 1987, 109, 18, 5546–5548Publication Date (Print):September 1, 1987Publication History Published online1 May 2002Published inissue 1 September 1987https://pubs.acs.org/doi/10.1021/ja00252a053https://doi.org/10.1021/ja00252a053research-articleACS PublicationsRequest reuse permissionsArticle...

Abstract Indole‐substituted purine nucleobases have been synthesized by Ru‐catalyzed oxidative annulation of 6‐anilinopurines with internal alkynes that involves CH activation. Unsymmetrical aryl(alkyl)alkynes led to high regioselectivity. The reaction was also successful nucleosides delivering unprotected indole‐substituted nucleosides. In the presence [RuCl 2 ( p ‐cymene)] and copper(II) acetate hydrate [Cu(OAc) ⋅H O], in some cases, we observed two‐fold activation products exhibit...

[Au]-catalyzed [3 + 3] cycloaddition reaction of enynones/enynals with azides, which allows the efficient regioselective synthesis highly fused furo[3,4-d][1,2,3]triazines in good-to-excellent yields under mild conditions, has been developed. The synthetic utility furanotriazines was exploited by oxidation cerium ammonium nitrate (CAN) affording functionalized dihydrotriazines. Both and dihydrotriazines exhibit good fluorescence activity.

Brønsted acid-mediated, transition-metal-free reaction of propargyl alcohols with sulfonamido-indoles/-indolines under mild conditions affords highly substituted δ- or α-carbolines in good to excellent yields. This protocol involves cascade sequences Friedel-Crafts alkylation/ [1,5]-hydrogen shift/electrocyclization/elimination/ [1,2]-aryl migration followed by aromatization. An unexpected regioselective tosyl group from indole 2- 6-position and arene elimination leading has also been discovered.

1-Methylindole-3-carboxamides react with substituted propargyl alcohols to afford lactams by [4 + 3]-annulation and carboxamide group migration the indole-2-position. In contrast, indole-2-carboxylic acids/amides form fused seven-membered lactones/lactams (oxepinoindolones/azepinoindolones) upon treatment using catalytic Cu(OTf)2. Decarboxylative cyclization of 1-methylindole-2- or indole-3-carboxylic acids under Lewis (for 1-methylindole-2-carboxylic acid) Brønsted...

Under metal-free conditions, δ-acetoxy allenoates react with cyclic N-sulfonyl imines (sulfamidate imines/sulfonyl imines) to afford functionalized 2-pyridinyl acetates (α-pyridyl acetates) or teraryl motifs by a simple Lewis base switch. Thus, while DBU/Na2CO3 combination-directed [3 + 3] annulation involves sulfonyl elimination via O-S C-S bond cleavage, affording acetates, Ph3P-catalyzed [4 2] leads teraryls Mannich coupling and C-N cleavage retention of the sulfamoyloxy group depending...

Spiro-annulation involving δ-acetoxy allenoate and alkyl benzoisothiazole dioxide (N-sulfonyl ketimine) triggered by DABCO/MeCO2H combination leads to an essentially single diastereomer via chemo- regiospecific [4 + 2]-carboannulation a new hydroxyl group is introduced. In contrast, DMAP-catalyzed benzannulation using the same reactants affords unsymmetrical m-teraryls Mannich coupling, sequential proton transfers, C–N bond cleavage. Here, serves as 4C-synthon carboannulation completely base...

DBU-catalyzed spiro-annulation and concomitant ring expansion/domino reaction of δ-acetoxy allenoates with cycl-2-ene-N-sulfonyl hydrazides afford ring-expanded (5 → 6, 6 7, 7 8) products. By contrast, cycl-3-ene/ane-N-sulfonyl hydrazones under similar conditions deliver pyrazole cores the same allenoate that involves allylic elimination in which serves as 3C-synthon. The key spirocyclic intermediates, well dienyl-amine are isolated characterized. An extension to (R)-(-)-carvone-derived...

Very short C−H···O, N−H···O, and O−H···O hydrogen bonds have been generated utilizing the cyclic phosphate [CH2(6-t-Bu-4-Me-C6H2O)2]P(O)OH (1). X-ray structures of (i) 1 (unsolvated, two polymorphs), 1·EtOH, 1·MeOH, (ii) [imidazolium]+[CH2(6-t-Bu-4-Me-C6H2O)2PO2]-·MeOH [2], (iii) [HNC5H4−NN−C5H4NH]2+[{CH2(6-t-Bu-4-Me-C6H2O)2PO2}2]2-.4CH3CN·H2O [3], (v) [K, 18-crown-6]+[{CH2(6-t-Bu-4-Me-C6H2O)2P(O)OH}{CH2(6-t-Bu-4-Me-C6H2O)2PO2}]-·2THF [4], (vi) 1·cytosine·MeOH [5], (vii) 1·adenine·1/2MeOH...