Palladium-catalyzed cross-coupling of unactivated aryl sulfides with arylzinc reagents under mild conditions.

Cross-coupling of general aryl alkyl sulfides with arylzinc reagents proceeds smoothly, even at room temperature or below, with a palladium-N-heterocyclic carbene (NHC) catalyst. When combined with reactions that are unique to organosulfurs, that is, the SNAr sulfanylation or Pummerer reaction, the cross-coupling offers interesting transformations that are otherwise difficult to achieve. An alkylsulfanyl group is preferentially converted whilst leaving the tosyloxy and chloro intact, which expands the variety of orthogonal cross-coupling.

Regiocontrolled palladium-catalyzed arylative cyclizations of alkynols.

Tuning the reactivity of arylpalladium intermediates enables control of catalytic arylative 5-exo and 6-endo cyclizations of alkynols. The two modes of cyclizations represent a rare example of controllable, regioselective difunctionalization of alkynes. The cyclizations are useful in offering a divergent synthesis of oxygen-containing heterocycles, which is of synthetic use for further derivatization. Formal synthesis of an hNK-1 receptor antagonist also showcases the utility of our arylative cyclization.

TIPS-TTF as a precursor of low-symmetry TTF derivatives: steric protection strategy in the regioselective C-H modification of TTF.

Triisopropylsilyltetrathiafulvalene (TIPS-TTF) has been devised as a promising platform for the synthesis of low-symmetry TTF derivatives. The bulky TIPS group allows TIPS-TTF to undergo palladium-catalyzed direct diarylation as well as LDA-mediated dilithiation exclusively on the roomier dithiole ring. Subsequent fluoride-mediated protodesilylation provided vicinally difunctionalized TTF, which could undergo further functionalization.

Synthesis of 1,2-disubstituted cyclopentenes by palladium-catalyzed reaction of homopropargyl-substituted dicarbonyl compounds with organic halides via 5-endo-dig cyclization.

Palladium catalysts with bulky biaryl phosphine ligands allow homopropargyl-substituted dicarbonyl compounds to undergo intramolecular addition via a rare 5-endo-dig pathway. C-C bond forming reductive elimination follows the addition to introduce alkenyl and alkynyl as well as aryl groups by using the corresponding organic halides. The cyclization is versatile enough to be applicable to the synthesis of highly substituted dihydropyrrole and a fused tricyclic compound.

Synthesis of alkylidenecyclopropanes by palladium-catalyzed reaction of propargyl-substituted malonate esters with aryl halides by anti-carbopalladation pathway.

Palladium-catalyzed arylative cyclization of propargyl-substituted malonate esters with aryl halides offers a stereoselective approach to alkylidenecyclopropanes. The reaction proceeds by an anti-carbopalladation pathway, which guarantees the exclusive stereocontrol of the resulting double bond. The highly strained as well as densely substituted skeletons of the products facilitate further versatile transformations, which underscores the importance of the products as synthetic intermediates.

Intermolecular reductive radical addition to 2-(2,2,2-trifluoroethylidene)-1,3-dithiane 1-oxide: experimental and theoretical studies.

Tin hydride mediated radical addition of organic halide to 2-(2,2,2-trifluoroethylidene)-1,3-dithiane 1-oxide has been devised. The reaction is equivalent to an unrealizable radical addition to trifluoromethylketene, providing useful α-trifluoromethyl carbonyl equivalents. The trifluoromethyl and the sulfoxide groups of the substrate play key roles for the success of the radical addition, lowering the barrier of the radical addition step and controlling the stereoselectivity of the reaction, which DFT calculations have elucidated.

Synthesis of 3-trifluoromethylbenzo[b]furans from phenols via direct ortho functionalization by extended Pummerer reaction.

A concise and diversity-oriented route to trifluoromethylbenzo[b]furans has been devised. A variety of phenols are directly converted to the corresponding 2-methylthio-3-trifluoromethylbenzo[b]furans by new triflic-anhydride-mediated extended Pummerer annulation reactions with trifluoromethylketene dithioacetal monoxide. The methylthio group of the products undergoes further transformations, which increase the diversity of available trifluoromethylbenzo[b]furans.

Palladium-catalyzed allylation of aryl halides with homoallyl alcohols bearing a trisubstituted double bond: application to chirality transfer from hydroxylated carbon to benzylic one.

A facile route to homoallyl alcohols bearing a trisubstituted double bond has been devised. The palladium-catalyzed reactions of aryl halides with the alcohols thus synthesized result in regiospecific allyl transfer from the alcohols to aryl halides via retro-allylation, providing allylarenes having two substituents at the 1 and 2 positions of the allyl moiety. Optically active homoallyl alcohols transfer their chirality at the hydroxylated carbon to the benzylic carbon of the product.

Palladium-catalysed arylative cyclisation of N-allylacetamides with aryl halides yielding benzyl-substituted oxazolines.

Treatment of N-allylacetamide with aryl halide in the presence of sodium t-butoxide and a palladium catalyst leads to arylative cyclisation to provide the corresponding benzyl-substituted oxazoline in high yield.