N. A. Bumagin

LIGANDLESS PALLADIUM CATALYZED REACTIONS OF ARYLBORONIC ACIDS AND SODIUM TETRAPHENYLBORATE WITH ARYL HALIDES IN AQUEOUS MEDIA

Polyfunctional biaryls are prepared by a modified Suzuki cross-coupling reaction between arylboronic acids or sodium tetraphenylborate and aryl halides ArX, Xue5fbI, Br, Cl in aqueous solvents or neat water using a phosphine-free palladium catalyst, and in the presence of bases (Na2CO3 or NaOH). All four phenyl groups of Ph4BNa participate in the reaction. The reaction of Ph4BNa with aryl halides proceeds in water with high catalytic efficiency (250,000 catalytic cycles).

PALLADIUM-CATALYZED CROSS-COUPLING REACTION OF ORGANOSTANNOATES WITH ARYL HALIDES IN AQUEOUS-MEDIUM

Abstract Water-soluble hydroxocomplexes 2 , easily formed from organotin trihalides 1 in aqueous alkaline solution, react readily with aryl halides in the same medium in the presence of palladium complexes to give cross-coupled products 3 in high yields.

Catalytic coupling of terminal acetylenes with iodoarenes and diaryliodonium salts in water

Abstract The catalytic coupling of terminal acetylenes with iodoarenes and diaryliodonium salts are shown to occur in aqueous K 2 CO 3 in the presence of 10 mol.% Bu 3 N under very mild conditions using PdCl 2 (PPh 3 ) 2 and CuI as catalyst precursor to give substituted tolans in high yields.

Palladium catalyzed cross-coupling reaction of Grignard reagents with halobenzoic acids, halophenols and haloanilines

Abstract Convenient syntheses of substituted benzoic acids, phenols and anilines have been achieved by using pall cross-coupling reactions between Grignard reagents and aryl halides containing carboxy, hydroxy and amino groups without a protection-deprotection sequence.

Synthesis of benzofurans via Pd2+-catalyzed oxidative cyclization of 2-allylphenols

Abstract Substituted 2-methylbenzofurans were obtained from 2-allylphenols via Pd2+-catalyzed oxidative cyclization using Cu(OAc)2–LiCl as a reoxidant and wet DMF as a solvent.

Reactions of organometallic compounds catalyzed by transition-metal complexes. XI: The palladium-catalyzed reaction of acyl chlorides with Et6Sn2 as a route to symmetrical ketones and α-diketones

Abstract The reaction of aroyl chlorides (ArCOCl) with Et6Sn2 gives symmetrical ketones (Ar2CO) or α-diketones ((ArCO)2), depending on the nature of the palladium catalyst and the reaction conditions. The synthesis of α-diketones from AlkCOCl and HetCOCl has been performed for Alk = n-C7H15 and Het = 2-C4H3O (furyl). The palladium-catalyzed carbonylation of aryl iodides in the presence of Et6Sn2 may serve as another route to symmetrical α-diketones. Such a possibility has been demonstrated for the preparation of 4,4′-dimethoxybenzil from 4-iodoanisole, carbon monoxide, and Et6Sn2.

Palladium-catalyzed synthesis of aromatic acid derivatives by carbonylation of aryl iodides and Alk3SnNu (Nu = MeO, Et2N, PhS, EtS)

Abstract Carbonylation of the ArI/Alk 3 SnNu system (Nu=MeO, Et 2 N), leading to esters and amides of substituted benzoic acids, occurs readily in the presence of phosphinepalladium complexes. When Nu = PhS and EtS either a cross-coupling product (Ar = p -NO 2 C 6 H 4 ) or a carbonylation product (Ar = Ph) is formed predominantly, depending on the nature of ArI. Stoichiometric reactions of ArPdI(PPh 3 ) 2 with carbon monoxide, resulting in acylpalladium complexes, and reactions of ArCOPdI(PPh 3 ) 2 with Alk 3 SnNu have been studied. Some mechanistic aspects are discussed.

The reaction of organotin compounds with derivatives of triarylmethane in CH2Cl2

Abstract The reaction of RSnMe3 with the triarylmethyl salts Ph3CBF4, (C6Cl5)3CSbCl6 and (p-NO2C6H4)3CBr was studied. It was shown that the reaction of RSnMe3 (R ue5fb CH3, CH2ue5fbCHCH2, C13H9 (9-fluorenyl), C9H7 (indenyl), PhCue5fcC and CN) with Ph3CBF4 is an electrophilic substitution process and that Ph3CR is formed quantitatively. The reactions of PhSnMe3 with Ph3CBF4 and RSnMe3 (R ue5fb CH3, CH2ue5fbCHCH2, Ph and PhCue5fcC) with (C6Cl5)3SbCl6 are redox processes. (p-NO2-C6H4)3CBr only reacts with RSnMe3 when R is a strong electron withdrawing group (R ue5fb 9-fluorenyl, indenyl and cyclopentadienyl) and (p-NO2C6H4)3CR and (p-NO2C6H4)3C. are formed. It is assumed that the reactions which give (p-NO2C6H4)3CR and (p-NO2C6H4)3C. are independent.

New synthesis of palladium catalyst immobilized on carbon nanotubes and its activity in certain organic reactions

A new catalyst is prepared using the direct reaction between carbon nanotubes and a zero valent palladium complex with the easily removed ligand, dibenzylideneacetone (dba). Micrographs are obtained, and dimensions of metal particles are measured. Suzuki, Heck, and Sonogashira reactions as well as hydrogenation of the carbon-carbon triple bond are efficiently catalyzed by this catalyst.

Reactions of organometallic compounds catalyzed by complexes of transition metals Communication 5. Organomagnesium, -zinc, -cadmium, and -aluminum compounds in allyldemetallation reactions catalyzed by palladium complexes

Conclusions1.Reactions of organometallic compounds RM (R=Ph, p-MeC6H4, p-BrC6H4, p-MeOC6H4, p-Me2NC6H4, PhCH2, PhCH=CH, 9-fluorenyl, 2-thienyl, PhC≡C; M=MgBr, ZnCl, CdBr, AlCl2) with CH2=CHCH2X (X = Br, OAc, OPh,+NEt3) catalyzedby Pd(PPh3)4 and (λ3-C3H5PdCl)2 in THF have been studied. The influence has been investigated of the nature of metal M, of the organic radical R, and of the leaving group X on the rate of allyl-demetallation and on the yield of products RCH2CH=CH2 and R2.2.The reactions of RMgBr (R=Ph, p-MeC6H4, p-BrC6H4, PhCH2, 9-fluorenyl, 2-thienyl) with CH2=CHCH2Br catalyzed by Pd(PPh3)4 proceeded significantly more rapidly and selectively than in the absence of palladium catalyst which made it possible to obtain the corresponding products of allyldemetallation under mild conditions and in high yield.3.The main possibility of allyldemetallation of Reformatsky reagents has been shown for the first time in the example of the reaction of BrZnCH2CO2Et with CH2=CHCH2Br catalyzed by (λ3-C3H5PdCl)2 and leading to the preparation of CH2=CHCH2CO2Et. The reaction is a convenient method for introducing the allyl group into theα-position of esters.