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Palladium-catalyzed, hydroxy-group-directed C-H arylation of [1,1'-biphenyl]-2-ols with chloroarenes was performed. The reaction showed a broad substrate scope and was successfully applied to pharmaceuticals containing a chloro group. Using 2-heteroarylphenols instead of [1,1'-biphenyl]-2-ols also yielded the desired products. The arylated product was further transformed into a triphenylene derivative.

A practical Pd-catalyzed carbonylation of (hetero)aryl bromides using a crystalline carbon monoxide (CO) surrogate, 2,4,6-trichlorophenyl formate (TCPF), was developed. This reaction proceeds without the slow addition technique that was previously required and with a low catalyst loading (1 mol%). The utility of this Pd-catalyzed external-CO-free carbonylation using TCPF was demonstrated in the synthesis of a histone deacetylase inhibitor.

The use of toxic gas surrogates in organic reactions instead of the gas itself contributes to enhancing the safety, practicality, and efficiency of the reactions involved. Our efforts toward the creation of toxic gas surrogates and the development of a series of catalytic reactions using these surrogates are described. Improvements in substrate scope during the hydroesterification of alkenes using formates facilitated by the Ru-imidazole catalyst system provided the opportunity to discover that phenyl formate is a useful carbon monoxide (CO) surrogate for the generation of CO and phenol under weakly basic conditions. This discovery triggered the development of highly reactive but stable CO surrogates and a variety of Pd-catalyzed carbonylative transformations. N-Formylsaccharin facilitated the use of additional nucleophiles in carbonylation reactions that provided access to a variety of carbonyl compounds. Detailed experimental and theoretical mechanistic studies into the generation of CO from phenyl formate suggest that CO generation proceeds via a concerted E2 α-elimination. Furthermore, a known surrogate of sulfur dioxide was applied for the first time to the selective syntheses of cyclic sulfonamides and sulfinamides, confirming that the surrogate operates as an "S=O" source. Notably, the reactions described herein are scalable and can be performed without the use of external toxic gases and specialized reaction vessels; they are easy and simple to perform and demonstrate enormous potential for industrial application.

We have developed a safe and practical synthetic method for preparing axially chiral diphenyl dicarboxylates using Pd-catalyzed external-CO-free carbonylation with phenyl formate as a CO surrogate. Optimized conditions consisted of axially chiral [1,1'-binaphthalene]-2,2'-diyl ditriflate and its congeners, each easily prepared from commercially available enantiomerically pure diols, Pd(OAc) 2 , 1,3-bis(diphenylphosphino)propane, ethyldiisopropylamine, and no solvent. To demonstrate the potential utility of these products, this method was conducted on gram-scale and the phenyl ester products were converted to other useful compounds, and both processes were carried out without difficulty.

N-formylsaccharin, an easily accessible crystalline compound, has been employed as an efficient CO source in Pd-catalyzed fluorocarbonylation of aryl halides to afford the corresponding acyl fluorides in high yields. The reactions use a near-stoichiometric amount of the CO source (1.2 equiv) and tolerate diverse functional groups. The acyl fluorides obtained could be readily transformed into various carboxylic acid derivatives such as carboxylic acid, esters, thioesters, and amides in a one-pot procedure.

The high utility of 2,4,6-trichlorophenyl formate, a highly reactive and easily accessible crystalline CO surrogate, is demonstrated. The decarbonylation with NEt(3) to generate CO proceeded rapidly at rt, thereby allowing external-CO-free Pd-catalyzed carbonylation of aryl/alkenyl halides and triflates. The high reactivity of the CO surrogate enabled carbonylation at rt and significantly reduced the quantities of formate to near-stoichiometric levels. The obtained trichlorophenyl esters can be readily converted to a variety of carboxylic acid derivatives in high yields.

Highly efficient palladium-catalyzed carbonylation of aryl, alkenyl, and allyl halides with phenyl formate is reported. This procedure does not use carbon monoxide and affords one-carbon-elongated carboxylic acid phenyl esters in excellent yields. The reaction proceeds smoothly under mild conditions and tolerates a wide range of functional groups including aldehyde, ether, ketone, ester, and cyano groups. Furthermore, a variety of heteroaromatic bromides can be converted to the corresponding phenyl esters in high yields.

Easy peasy: The title reaction employs N‐formylsaccharin, which is an easily accessible crystalline compound, as an effective CO source. The reactions proceed with a small excess of the CO source at moderate temperatures and were successfully applied to a wide range of aryl bromides. DMF=N,N‐dimethylformamide, dppb=1,4‐bis‐(diphenylphosphino)butane. [ABSTRACT FROM AUTHOR]

Abstract: Palladium-catalyzed carbonylation of tosylates with phenyl formate is described. This procedure needs neither external carbon monoxide nor any pressure-resistant apparatus. A variety of cyclic and acyclic alkenyl tosylates can be converted into the corresponding phenyl esters in good yields. Furthermore, this method is effective for the one-pot synthesis of α,β-unsaturated amides. [Copyright &y& Elsevier]

• Synthesis of 2,3-disubstituted indoles bearing 2-hydroxyphenyl groups at the C3 positions has been achieved. • Readily available chlorophenols can be used as substrates. • Only the Pd–DHTP catalyst can effectively catalyze the desired reaction. • 2-Chloro group of 2,4-dichlorophenol reacts selectively. 2,3-Disubstituted indoles bearing 2-hydroxyphenyl moieties at their C3 positions were synthesized from readily available 2-chlorophenols and alkynylanilines via aminopalladation/reductive elimination using Pd–dihydroxyterphenylphosphine catalyst. The catalyst accelerates the introduction of the 2-hydroxyphenyl group at the C3 position of the indole. [ABSTRACT FROM AUTHOR]

Multisubstituted pyrroles were prepared by Pd-catalyzed site-selective arylation of 2,5-disubstituted 1 H -pyrroles with aryl chlorides, triflates, or nonaflates. Site-selectivity of the reaction was controlled using appropriate ligands, and 2,2,5-trisubstituted 2 H -pyrroles were synthesized via dearomative C2-arylation. Moreover, 2,3,5-trisubstituted 1 H -pyrroles were successfully fabricated by direct C3-arylation. These arylations can be applied to the pharmaceuticals bearing aryl chloride moieties. Additionally, 2,2,5-triaryl-2 H -pyrroles were converted into multiarylated pyrrolines and pyrrolidines, which will be useful in synthetic and medicinal chemistry. [Display omitted] • Pd-catalyzed site-selective arylation of pyrroles has been achieved. • Aryl chlorides, triflates, and nonaflates were successfully used as arylating agents. • Pharmaceuticals bearing aryl chloride moieties were also used as arylating agents. • 2,2,5,5-Tetraarylpyrrolidines were efficiently synthesized. [ABSTRACT FROM AUTHOR]