High throughput synthesis of diverse 2,5-disubstituted indoles using titanium carbenoids bearing boronate functionality

Synthesis of diverse indole libraries on polystyrene resin - Scope and limitations of an organometallic reaction on solid supports

The synthesis of diverse substituted indole structures on solid supports is described. The immobilization of nitrobenzoic acid onto Merrifield resin and the subsequent treatment with alkenyl Grignard reagents delivered indole carboxylates bound to solid supports. In contrast to results in the liquid phase, ortho,ortho-unsubstituted nitroarenes also delivered indole moieties in good yields. Subsequent palladium-catalyzed reactions (Suzuki, Heck, Sonogashira, Stille) delivered, after cleavage, the desired molecules in moderate to good yields over four steps. The scope and limitations are presented.

Synthesis and reactivity of solid-supported organotrifluoroborates in Suzuki cross-coupling

Solid-supported organotrifluoroborates were prepared in high yields by ion exchange with Amberlyst resins. The reactivity of solid supported aryltrifluoroborates was evaluated in Suzuki-Miyaura couplings with numerous aryl bromide partners. Electron-rich and -poor substituents were tolerated on both substrates, providing yields up to 90%. Examples of alkyl-, alkenyl-, alkynyl-, and heteroaryltrifluoborates were also successfully cross-coupled to aryl halides.

Synthesis and diversification of 1,2,3-triazole-fused 1,4-benzodiazepine scaffolds

A substituted heterocyclic scaffold comprising a 1,4-benzodiazepine fused with a 1,2,3-triazole ring has been synthesized and diversified via a variety of refunctionalizations. The strategy features the rapid assembly of the scaffold by combining 3-4 reactants in an efficient multicomponent assembly process, followed by an intramolecular Huisgen cycloaddition.

Uniting anion relay chemistry with Pd-mediated cross coupling: design, synthesis and evaluation of bifunctional aryl and vinyl silane linchpins

Union of type II Anion Relay Chemistry (ARC) with Pd-induced Cross Coupling Reactions (CCR) has been achieved, in conjunction with the design, synthesis, and evaluation of a new class of bifunctional linchpins, comprising a series of vinyl silanes bearing beta- or gamma-electrophilic sites. The synthetic tactic permits both alkylation and Pd-mediated CCR of the anions derived via 1,4-silyl C(sp(2))-->O Brook Rearrangements.

Regioselective intramolecular dipolar cycloaddition of azides and unsymmetrical alkynes

Enantioenriched allenylsilanes are used in three-component propargylation reactions with aldehydes and silyl ethers to form syn-homopropargylic ethers that contain an imbedded azide. These materials then undergo thermally induced intramolecular 1,3-dipolar cycloaddition reactions, resulting in unique fused ring systems containing 1,2,3-triazoles. The ability to modify all three components of the reaction allows for expedient access to compounds containing significant structural and stereochemical variation.