A Nickel(0)-Catalyzed Process for the Transformation of Enynes to Bicyclic Cyclopentenones

A Nickel(0)-Catalyzed Process for the Transformation of Enynes to Bicyclic Cyclopentenone

A Domino Copper-Catalyzed C−O Coupling−Claisen Rearrangement Process

A practical method for the diastereoselective generation of two adjacent quarternary stereocenters by combining a copper-catalyzed C−O coupling reaction with a subsequent Claisen rearrangement in a one-pot domino process is described. Furthermore, an experimentally simple method for the stereoselective synthesis of a variety of different types of vinyl ethers is delineated using the same catalyst system

An Air and Thermally Stable One- Component Catalyst for the Amination of Aryl Chlorides

In this paper we report a new, highly efficient palladacyclic precatalyst that is air, moisture, and thermally stable and obviates the need to employ a glovebox. We have developed a convenient one-component precatalyst for the amination of aryl chlorides that overcomes many of the limitations of those previously described

Versatile Enantioselective Synthesis of Functionalized Lactones via Copper-Catalyzed Radical Oxyfunctionalization of Alkenes

A versatile method for the rapid synthesis of diverse enantiomerically enriched lactones has been developed based on Cu-catalyzed enantioselective radical oxyfunctionalization of alkenes. The scope of this strategy encompasses a series of enantioselective difunctionalization reactions: oxyazidation, oxysulfonylation, oxyarylation, diacyloxylation, and oxyalkylation. These reactions provide straightforward access to a wide range of useful chiral lactone building blocks containing tetrasubstituted stereogenic centers, which are hard to access traditionally

An Improved Protocol for the Pd-Catalyzed α-Arylation of Aldehydes with Aryl Halides

An improved protocol for the Pd-catalyzed α-arylation of aldehydes with aryl halides has been developed. The new catalytic system allows for the coupling of an array of substrates including challenging electron-rich aryl bromides and less reactive aryl chlorides. The utility of this method has been demonstrated in a new total synthesis of (±)-sporochnol

Dynamic Kinetic Resolution via Asymmetric Conjugate Reduction: Enantio- and Diastereoselective Synthesis of 2,4-Dialkyl Cyclopentanones

Herein, we report the kinetic and the dynamic kinetic resolutions of racemic 3,5-dialkyl-2-cyclopenten-1-ones. Kinetic resolution, with good selectivity factors (25−52), was achieved by conjugate reduction with catalytic CuCl/NaOt-Bu/(S)-p-tol-BINAP and stoichiometric quantities of poly(methylhydrosiloxane) (PMHS). When stoichiometric amounts of NaOt-Bu and t-BuOH were included in the reaction mixture, rapid racemization of the starting material occurred allowing for the dynamic kinetic resolution of the cyclopentenone substrates. In this process, chiral 2,4-dialkylcyclopentanones were isolated with high stereoselectivity (ee ≥ 91%, dr ≥ 90:10) and in high yield (≥89%)

Palladium-Catalyzed Intermolecular Coupling of Aryl Halides and Amides

The first general intermolecular C−N bond-forming reactions between aryl halides and amides were realized using a palladium catalyst with Xantphos as the ligand. Aryl triflates, carbamates, and sulfonamides are also viable substrates for the amidations, which proceed at 45−110 °C with 1−4 mol % of Pd catalyst in 66−99% yields and exhibit good functional group compatibility

Palladium-Catalyzed Regioselective Hydrodebromination of Dibromoindoles: Application to the Enantioselective Synthesis of Indolodioxane U86192A

A novel approach to the selective preparation of 4-bromoindoles was developed via Pd(OAc)2/rac-BINAP catalytic reactions. A variety of 4,6-dibromoindoles were transformed to 4-bromoindoles with high regioselectivity. This methodology, along with C−N and C−O bond-forming reactions developed in our laboratory, was applied to the enantioselective synthesis of indolodioxane U86192A, an antihypertensive agent

<i>P</i>-Chirogenic Binaphthyl-Substituted Monophosphines: Synthesis and Use in Enolate Vinylation/Arylation Reactions

New phosphine ligands possessing both axial chirality and a chirogenic phosphorus center were prepared from (R)-2-bromo-2‘-N,N-(dimethylamino)-1,1‘-binaphthyl (1) via a simple Li−halogen exchange protocol. The asymmetric vinylation of a ketone enolate with (R,RP)-2-(tert-butylphenylphosphino)-2‘-N,N-(dimethylamino)-1,1‘-binaphthyl (2a) afforded the coupling product with good enantiomeric excess

An Improved System for the Palladium-Catalyzed Borylation of Aryl Halides with Pinacol Borane

A highly efficient method for the palladium-catalyzed borylation of aryl halides with an inexpensive and atom-economical boron source, pinacol borane, has been developed. This system allows for the conversion of aryl and heteroaryl iodides, bromides, and several chlorides, containing a variety of functional groups, to the corresponding pinacol boronate esters. In addition to the increase in substrate scope, this is the first general method where relatively low quantities of catalyst and short reaction times can be employed