Asymmetric synthesis of abietane diterpenoids via B-alkyl Suzuki-Miyaura coupling. Formal total asymmetric synthesis of 12-deoxyroyleanone and cryptoquinone

A convergent synthetic strategy for abietane diterpenoids via B-alkyl Suzuki-Miyaura coupling and Lewis acid-mediated cyclization reactions is established. Asymmetric total synthesis of 12-deoxyroyleanone, an antileishmanial diterpene, is described.     

Imidazol(in)ium carboxylates as N-heterocyclic carbene ligand precursors for Suzuki-Miyaura reactions

Simple catalysts formed in situ from palladium acetate and a variety of imidazolium and imidazolinium carboxylates and dithiocarboxylates have been screened in the coupling of aryl halides with trans-2-phenylvinylboronic acid. Imidazol(in)ium carboxylates show an excellent activity, which compares to that displayed by the parent imidazol(in)ium chlorides, whereas imidazol(in)ium dithiocarboxylates are poorly efficient. Interestingly, the base employed exerts a profound influence on the trans/cis stereochemistry of the coupling product.     

Microwave-promoted Suzuki-Miyaura coupling reactions in a cycloalkane-based thermomorphic biphasic system

Microwave-promoted Suzuki-Miyaura coupling reaction of aryl halides attached to a cycloalkane-soluble platform was accomplished in a cycloalkane-based thermomorphic biphasic system. Following irradiation and subsequent cooling, the monophasic reaction mixture immediately formed a biphasic solution to allow facile workup and separation of the product.     

Synthesis and absolute configuration of cordiaquinone K, antifungal and larvicidal meroterpenoid isolated from the Panamanian plant, Cordia curassavica

Total synthesis of cordiaquinone K, a new antifungal and larvicidal meroterpenoid, is reported. The absolute configuration of cordiaquinone K was confirmed by the synthesis.     

Efficient, protection-free Suzuki-Miyaura synthesis of ortho-biphenyltetrazoles

We describe an efficient protocol for the Suzuki-Miyaura synthesis of ortho-biphenyltetrazoles from non-protected 2-bromophenyltetrazole and arylboronic acids. The optimised conditions were achieved using [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) as catalyst and Na₂CO₃ as base. A panel of structurally diverse arylboronic acids was used to demonstrate the scope of the coupling procedure.     

Microwave-assisted Suzuki-Miyaura and Heck-Mizoroki cross-coupling reactions of aryl chlorides and bromides in water using stable benzothiazole-based palladium(II) precatalysts

The catalytic activity of benzothiazole-based Pd(II)-complexes was evaluated in Suzuki-Miyaura and Heck-Mizoroki C-C cross-coupling reactions of aryl chlorides and bromides with olefins and arylboronic acids both under thermal as well as microwave irradiation conditions in water. The factors affecting the optimization of such reactions as well as the reusability of the Pd-precatalysts are studied.     

Synthesis of 5-arylhistidines via a Suzuki-Miyaura cross-coupling

Microwave irradiation efficiently promoted the Suzuki-Miyaura reaction of a 5-bromohistidine with various arylboronic acids in the presence of a palladium catalyst. This methodology allowed the synthesis of histidines substituted at position 5 of the imidazole ring with a phenyl, a substituted phenyl, a pyridyl or a thienyl ring. The corresponding 5-arylhistidines were obtained in moderate to good yields.     

Highly regio- and stereoselective hydrometallation reactions of fluorine-containing internal alkynes: Novel approaches to fluoroalkylated alkenes

Hydroalumination, hydrocupration, and hydroboration reactions of various fluorine-containing alkynes were investigated. The alkyne reacted smoothly with 2.0 equiv. of Red-Al at −78 °C to give the hydroaluminated adduct in a highly regio- and stereoselective manner, which was treated with iodine, the corresponding vinyliodide being produced in moderate yield. Hydrocupration of the alkynes also took place, but the resulting vinylmetal reacted with various electrophiles sluggishly. In sharp contrast, the reaction with dicyclohexylborane proceeded smoothly to afford the cis-addition products preferentially, which were subjected to Suzuki-Miyaura cross-coupling reaction, leading to trisubstituted alkenes in high yields.     

Efficient synthesis of various acycloalkenyl derivatives of pyrimidine using cross-metathesis and Pd(0) methodologies

Novel acyclonucleosides (9a-d, 10a-d, 18a,b and 19a,b) have been prepared using Pd(0) and cross-metathesis methodologies. The allylic N-alkylation under Tsuji-Trost conditions was used to introduce the nucleobase, while the Suzuki-Miyaura reaction afforded C-5 substituted uracil analogues. The cross-metathesis performed with a ruthenium catalyst was used to provide new acycloalkenyl nucleosides. The antiviral activities of all final compounds have been evaluated.     

Preparation of polymer-supported phosphine from ferrocene for palladium-catalyzed Suzuki-Miyaura cross-coupling reactions

Polymer-supported phosphine ligand 3b derived from ferrocene was prepared,and applied in palladium-catalyzed Suzuki- Miyaura reactions.A range of aryl bromides can couple with phenylboronic acid to obtain corresponding biaryls in excellent yields. The recycling of the polymer-bound catalyst was tested without adding palladium.