Three Fluorines at Once The trifluoromethyl (CF 3 ) group is playing an increasingly important role in the design of pharmaceutical and agrochemical compounds. CF a powerful attractor electron density within given molecular framework, recently fluorine-hydrocarbon interactions have emerged as distinct complement to more traditional hydrophilic/hydrophobic interplay that governs docking between small molecules proteins. Cho et al. (p. 1679 now present efficient method for appending groups...

Facile Fluorination Fluorine atoms have become a useful substituent in pharmaceuticals. However, they remain challenging to introduce synthetically because present methods for carbon-fluorine bond formation require either corrosive conditions or somewhat exotic, and thus expensive, reagents. A sticking point has been the failure of traditional palladium catalysts couple aryl groups with coordinated fluoride. Watson et al. (p. 1661 , published online 13 August; see Perspective by Gouverneur )...

A catalyst system based on a new biarylmonophosphine ligand (BrettPhos) that shows excellent reactivity for C−N cross-coupling reactions is reported. This enables the use of aryl mesylates as coupling partner in bond-forming reactions. Additionally, BrettPhos permits highly selective monoarylation an array primary aliphatic amines and anilines at low loadings with fast reaction times, including first methylamine. Lastly, oxidative addition complexes are included, which provide insight into...

No pressure, no worries: A general, functional-group-tolerant, mild system for the Pd-catalyzed carbonylation of aryl chlorides to corresponding amides has been developed. The catalyst operates at 1 atm CO using an inexpensive, air-stable, and commercially available ligand (see scheme, Cy=cyclohexyl). Sodium phenoxide is a critical additive in this transformation; its role studied situ IR spectroscopy.

A method for the Pd-catalyzed carbonylation of aryl bromides has been developed using Xantphos as ligand. This is effective direct synthesis Weinreb amides, 1° and 2° benzamides, methyl esters from corresponding at atmospheric pressure. In addition, a putative catalytic intermediate, (Xanphos)Pd(Br)benzoyl, was prepared an X-ray crystal structure obtained revealing unusual cis-coordination mode in this palladium−acyl complex.

We report efficient syntheses of axially chiral biaryl amides in yields ranging from 80−92%, and with enantioselectivity the range 88−94% ee employing an asymmetric Suzuki−Miyaura process Pd(OAc)2 KenPhos as ligand. These studies demonstrate that electron-rich electron-deficient o-halobenzamides can be efficiently coupled 2-methyl-1-naphthylboronic acid 2-ethoxy-1-naphthylboronic acid. The selectivities reactions are independent nature halogen substituent on benzamide coupling partner. Our...

In situ combination of diphosphinic amides and Zr(NMe(2))(4) results in the formation chiral zirconium bis(amido) complexes. The complexes are competent catalysts for intramolecular asymmetric alkene hydroamintion, providing piperidines pyrrolidines up to 80% ee high yield. This system utilizes an inexpensive precatalyst readily prepared ligands is first hydroamination catalyst based upon a neutral complex.

The reaction of 2,5-dimethylfuran and ethylene to produce p-xylene represents a potentially important route for the conversion biomass high-value organic chemicals. Current preparation methods suffer from low selectivity number byproducts. Using modern separation analytical techniques, structure many byproducts produced in this when HY zeolite is employed as catalyst has been identified. From these data, detailed network proposed demonstrating that hydrolysis electrophilic alkylation...

Installing silicon is easy! A high-yielding protocol for the palladium-catalyzed silylation of terminal alkenes reported. This method allows facile conversion styrenes to E-β-silyl by using iodotrimethylsilane (TMSI) or chlorotrimethylsilane/lithium iodide (see scheme). Terminal allyl silanes with good E/Z ratios are also readily accessed from α-olefins.

A route to renewable phthalic anhydride (2-benzofuran-1,3-dione) from biomass-derived furan and maleic (furan-2,5-dione) is investigated. Furan were converted in two reaction steps: Diels–Alder cycloaddition followed by dehydration. Excellent yields for the between maleic-anhydride obtained at room temperature solvent-free conditions (SFC) yielding 96% exo-4,10-dioxa-tricyclo[5.2.1.0]dec-8-ene-3,5-dione (oxanorbornene dicarboxylic anhydride) after 4 h of reaction. It shown that this...

We report the first example of a boryl-Heck reaction using an electrophilic boron reagent. This palladium-catalyzed process allows for conversion terminal alkenes to trans-alkenyl boronic esters commercially available catecholchloroborane (catBCl). In situ transesterification rapid access variety esters, amides, and other alkenyl adducts.

We report the first example of a silyl-Negishi reaction between secondary zinc organometallics and silicon electrophiles. This palladium-catalyzed process provides direct access to alkyl silanes. The delicate balance steric electronic parameters employed DrewPhos ligand is paramount suppressing isomerization promoting efficient selective cross-coupling.

We report an asymmetric homocoupling of ortho-(iodo)arylphosphine oxides and ortho-(iodo)arylphosphonates resulting in highly enantioenriched axially chiral bisphosphine bisphosphonates. These products are readily converted to biaryl bisphosphines without need for auxiliaries or optical resolution. This provides a practical route the development previously uninvestigated atroposelective ligands. The conditions have also proven effective dimerization other, non-phosphorus-containing aryl halides.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCarbonylation of Aryl Chlorides with Oxygen Nucleophiles at Atmospheric Pressure. Preparation Phenyl Esters as Acyl Transfer Agents and the Direct Alkyl Carboxylic AcidsDonald A. Watson, Xuexiang Fan, Stephen L. Buchwald*View Author Information Department Chemistry, Room 18-490, Massachusetts Institute Technology, Cambridge, 02139[email protected]Cite this: J. Org. Chem. 2008, 73, 18, 7096–7101Publication Date (Web):August 23, 2008Publication...

Kein Druck, kein Stress: Ein allgemein anwendbares, mildes System für die Pd-katalysierte Carbonylierng von Arylchloriden zu den entsprechenden Amiden wurde entwickelt. Der Katalysator enthält einen einfachen, luftstabilen und kommerziell erhältlichen Liganden arbeitet bei 1 atm CO-Druck (siehe Schema, Cy=Cyclohexyl). Entscheidend ist der Zusatz Natriumphenoxid, dessen Rolle durch In-situ-IR-Spektroskopie untersucht wurde.

Vinyl silyl ethers and disiloxanes can now be prepared from aryl-substituted alkenes related substrates using a silyl-Heck reaction. The reaction employs commercially available catalyst system mild conditions. This work represents highly practical means of accessing diverse classes vinyl ether in an efficient direct manner with complete regiomeric geometric selectivity.

Using rational ligand design, we have developed of a second-generation ligand, bis(3,5-di-tert-butylphenyl)(tert-butyl)phosphine, for the preparation allylsilanes using palladium-catalyzed silyl-Heck reaction. This new provides nearly complete suppression starting material alkene isomerization that was observed with our first-generation catalyst, providing vastly improved yields from simple materials. The studies quantifying electronic and steric properties are described. Finally, report an...

Using a palladium catalyst supported by DrewPhos, the alkylation of monochlorosilanes with primary and secondary alkyl-magnesium halides is now possible. Arylation sterically demanding aromatic magnesium also enabled. This transformation overcomes high bond strength Si-Cl (113 kcal/mol) rare example transition-metal catalyzed process involving its activation. Due to availability both chlorosilanes organomagnesium halide reagents, this method allows for preparation wide range alkyl aryl silanes.

The preparation of unsaturated secondary lactams via the palladium-catalyzed cyclization O-phenyl hydroxamates onto a pendent alkene is reported. This method provides rapid access to broad range that are widely useful building blocks in alkaloid synthesis. Mechanistic studies support an aza-Heck-type pathway.

For the first time, a general catalytic procedure for cross-coupling of primary amides and alkylboronic acids is demonstrated. The key to success this reaction was identification mild base (NaOSiMe3) oxidant (di-tert-butyl peroxide) promote copper-catalyzed in high yield. This transformation provides facile, high-yielding method monoalkylation amides.

We report a highly cross- and atroposelective coupling between ortho-(chloro)arylphosphine oxides ortho-(bromo)aryl ethers. This previously unknown asymmetric nickel-catalyzed reaction offers direct route to enantioenriched axially chiral biaryl monophosphine that are difficult access by other means. These products can be readily reduced generate MOP-type ligands bearing complex skeletal backbones. The utility of these in catalysis is also demonstrated.

The C-alkylation of nitroalkanes under mild conditions has been a significant challenge in organic synthesis for more than century. Herein we report simple Cu(I) catalyst, generated situ, that is highly effective C-benzylation using abundant benzyl bromides and related heteroaromatic compounds. This process, which believe proceeds via thermal redox mechanism, allows access to variety complex reaction represents the first step toward development general catalytic system alkylation nitroalkanes.

The preparation of tertiary nitroalkanes via the nickel-catalyzed alkylation secondary using aliphatic iodides is reported. Previously, catalytic access to this important class has not been possible due inability catalysts overcome steric demands products. However, we have now found that use a nickel catalyst in combination with photoredox and light leads much more active catalysts. These can nitroalkanes. conditions are scalable as well air moisture tolerant. Importantly, reduction...