Palladium-Catalyzed Dehydroarylation of Triarylmethanols and Their Coupling with Unsaturated Compounds Accompanied by C−C Bond Cleavage

[a] chem_201003643_sm_miscellaneous_information.pdf S1General Information: Glassware and Handling:All experiments were carried out in flame dried or oven dried (150 o C) glassware, in an atmosphere of nitrogen, unless specified otherwise, by standard Schlenk techniques. Schlenk reaction tubes with screwcaps, and equipped with a Teflon-coated magnetic stirbar were flame dried under vacuum and allowed to return to room temperature prior to being charged with reactants. A manifold permitting switching between nitrogen atmosphere and vacuum was used to control the atmosphere in the reaction vessel. Once charged with all the reactants, the reaction vessel was cycled through at least 3 cycles of nitrogen-vacuumnitrogen to ensure the atmosphere was inert.Reaction temperature refers to the temperature of the oil bath. Solvents and ReagentsAll solvents used for extraction, filtration and chromatography were of commercial grade, and used without further purification, except for pentane, which was distilled prior to use. Peptide Synthesis grade DMF used for reaction was purchased from BIOSOLVE BV (The Netherlands) and degassed by a freeze-pump-thaw procedure (repeated cycles of freezing under vacuum with liquid nitrogen and thawing to room temperature) prior to use. The degassing was performed regularly in small batches, and once degassed, the DMF was used within a few days.Reagents were purchased from Sigma-Aldrich, Strem or Acros and used without further purification. Analytical grade tri-n-butylamine was purchased from Sigma-Aldrich and stored in an atmosphere of nitrogen. Palladium complex Pd II -NHC was synthesized as described in literature [1] and stored under ambient conditions. Palladium complex Pd 0 -NHC was purchased from Sigma-Aldrich and stored in a nitrogen-filled glovebox, from which the requisite amounts were weighed out. S2Analysis TLC was performed on Merck silica gel 60, 0.25 mm plates and visualization was done by UV and staining with Seebach's reagent (a mixture of phosphomolybdic acid (25 g), cerium (IV) sulfate (7.5 g), H 2 O (500 mL) and H 2 SO 4 (25 mL)). GC-MS measurements were made using a HP 6890 Series Gas Chromatograph system equipped with a HP 5973 Mass Sensitive Detector. GC measurements were made using a Shimadzu GC 2014 gas chromatograph system bearing a AT5 column (Grace Alltech) and FID detection. Whenever GC yield is reported, the quantification was done using cyclo-octane as internal standard.High Resolution Mass measurements were performed using a ThermoScientific LTQ Oribitrap XL spectrometer.

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“…Characterization data matches with those reported in literature [2] Preparation of 4,4-diphenylbutan-2-one (3f).…”

Section: S3supporting

confidence: 85%

Pd–NHC Catalyzed Conjugate Addition versus the Mizoroki–Heck Reaction

Gottumukkala

Vries

Minnaard

2011

Chemistry A European J

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“…As for β‐aryl group elimination, Miura and co‐workers disclosed that the palladium‐catalyzed cross‐coupling of aryl halides to give biaryls proceeds with trisubstituted aryl methanols as coupling partners 3. They also reported the palladium‐catalyzed hydroarylation of enones with trisubstituted aryl methanols, although the reaction requires severe reaction conditions (xylene, 160 °C) 3c. Recently, stoichiometric β‐phenyl elimination on rhodium was reported by Hartwig and co‐workers, in which rhodium tert ‐alkoxide complexes [Rh(OCR 2 Ph)(PEt 3 ) 3 ] generate the phenylrhodium complex [RhPh(PEt 3 ) 3 ] and the corresponding ketones under mild conditions 8.…”

Section: Methodsmentioning

confidence: 99%

Rhodium‐Catalyzed Aryl Transfer from Trisubstituted Aryl Methanols to α,β‐Unsaturated Carbonyl Compounds

Nishimura¹,

Katoh²,

Hayashi³

2007

Angew Chem Int Ed

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In transition-metal-catalyzed organic reactions involving carbon-carbon bond formation, a carbon-metal catalyst bond is often generated by transmetalation of the organic group in an organometallic reagents. For example, in the rhodium-catalyzed conjugate arylation of electron-deficient alkenes, a wide variety of arylating reagents composed of B, Si, Zn, Sn, and Ti have been used for the formation of aryl rhodium intermediates by transmetalation (Scheme 1).[1] On the other hand, it has been recently reported that organotransition-metal species can be generated from metal alkoxides through b-hydrocarbyl elimination (Scheme 2) in some catalytic organic transformations. [2][3][4][5][6][7] As for b-aryl group elimination, Miura and co-workers disclosed that the palladium-catalyzed cross-coupling of aryl halides to give biaryls proceeds with trisubstituted aryl methanols as coupling partners.[3] They also reported the palladium-catalyzed hydroarylation of enones with trisubstituted aryl methanols, although the reaction requires severe reaction conditions (xylene, 160 8C).[3c] Recently, stoichiometric b-phenyl elimination on rhodium was reported by Hartwig and co-workers, in which rhodium tert-alkoxide complexes [Rh(OCR 2 Ph)(PEt 3 ) 3 ] generate the phenylrhodium complex [RhPh(PEt 3 ) 3 ] and the corresponding ketones under mild conditions.[8] During our efforts to realize catalytic organic transformations utilizing the b-hydrocarbyl elimination process on transition-metal alkoxides, [5b, 6a-d] we found that the acridinols 1 (Bn = benzyl), which are readily obtained by Grignard addition to 10-benzylacridin-9(10H)-one (2), are highly reactive towards b-aryl elimination on their alkoxide complexes. Herein, we describe the rhodium-catalyzed conjugate arylation of a,b-unsaturated carbonyl compounds with the trisubstituted aryl methanols 1 as aryl transfer reagents.In the first set of experiments, several types of a,asubstituted benzylalcohols were examined for their reactivity in the rhodium-catalyzed 1,4-addition to 3-nonen-2-one (3 a; Scheme 3, Table 1). In the presence of [{Rh(OH)(cod)} 2 ] (cod = cycloocta-1,5-diene) as a catalyst in toluene at 110 8C for 3 h, the starting enone 3 a was recovered intact with 2-phenyl-2-propanol (4 m), triphenylmethanol (5 m), and cyclic alcohols 6 m and 7 m.[9] The reaction of xanthenol 8 m, which has been reported to be a good phenyl donor in the palladium-catalyzed cross-coupling with aryl halides, [3a] gave the 1,4-addition product 9 am, but its yield was low (22 %; Table 1, entry 1). Acridinol 1 m was found to be much more reactive than the others towards the present rhodiumcatalyzed 1,4-addition to give 9 am in quantitative yield (Table 1, entry 2). The eliminated ketone, acridinone 2, was recovered in high yield (86 %). Scheme 1. Rhodium-catalyzed 1,4-addition of aryl organometallic reagents.Scheme 2. b-Hydrocarbyl elimination.Scheme 3. Rhodium-catalyzed conjugate arylation of a,b-unsaturated carbonyl compounds through b-aryl elimination.

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“…MeOH, 25 bar H 2 , 30 °C, 16 h L6 91% ee (8) Mixtures of Chiral and Achiral Monodentate Ligands in Asymmetric Rh-catalyzed Olefin Hydrogenation. 6b,c The concept of using mixtures of monodentate ligands in a combinatorial manner in order to influence enantio-or regioselectivity of transition metal-catalyzed processes has been extended to include diastereoselectivity.…”

Section: A Simple and Practical Protocol For The Palladium-catalyzedmentioning

confidence: 99%

“…The first examples of the skeletal rearrangement of enynes by the endocyclic cyclization pathway are also documented (eq 11). 8 Triarylmethanols are effectively dehydroarylated and reacted with some unsaturated compounds by using an appropriate palladium catalyst system such as Pd(OAc) 2 -P(1-nap) 3 to give the corresponding arenes and hydroarylation (eqs 12-15). Heck Reaction: Further Suggestions on the Mechanism.…”

Section: Highly Reactive Cationic Phosphine Gold(i) Complexescatalyzementioning

confidence: 99%

Tri(1-naphthyl)phosphine

Chen

2009

Encyclopedia of Reagents for Organic Synthesis

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Palladium-Catalyzed Dehydroarylation of Triarylmethanols and Their Coupling with Unsaturated Compounds Accompanied by C−C Bond Cleavage

Cited by 77 publications

References 11 publications

Pd–NHC Catalyzed Conjugate Addition versus the Mizoroki–Heck Reaction

Pd–NHC Catalyzed Conjugate Addition versus the Mizoroki–Heck Reaction

Rhodium‐Catalyzed Aryl Transfer from Trisubstituted Aryl Methanols to α,β‐Unsaturated Carbonyl Compounds

Tri(1-naphthyl)phosphine

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