Lewis Acid-Catalyzed Formal [4 + 2] Reaction of Alkynyl Sulfides and 2-Pyrones To Access Polysubstituted Aryl Sulfides

A practical and efficient method to access polysubstituted aryl sulfides has been discovered via a Lewis acid-catalyzed reaction between alkynyl sulfide and 2-pyrone, involving a Diels-Alder/retro-Diels-Alder pathway. Alkynyl sulfide as an electron-rich dienophile and 2-pyrones as electron-poor dienes are conjunctively transformed into a series of polysubstituted aryl sulfides with broad functional group compatibility in good to excellent yields (40 examples, 43-88% yield). The robustness and practicality of the protocol has been demonstrated through gram-scale synthesis and the ease of transformation of the resulting products.

Synthesis, Structure, and Catalytic Reactivity of Pd(II) Complexes of Proline and Proline Homologs

Palladium(II) acetate reacts with proline and proline homologs in acetone/water to yield square planar bis-chelated palladium amino acid complexes. These compounds are all catalytically active with respect to oxidative coupling of olefins and phenylboronic acids. Some enantioselectivity is observed and formation of products not reported in other Pd(II) oxidative couplings is seen. The crystal structures of nine catalyst complexes were obtained. Extended lattice structures arise from N-H••O or O••(HOH)••O hydrogen bonding. NMR, HRMS, and single-crystal XRD data obtained on all are evaluated.

Recyclable imidazolium ion-tagged nickel catalyst for microwave-assisted C–S cross-coupling in water using sulfonyl hydrazide as the sulfur source

Recyclable nickel(ii) catalyst promoted sulfenylation of aryl halides with sulfonyl hydrazides in water using microwave irradiation under mild conditions is reported.

The chemistry of ynol and thioynol ethers

Alkynyl ethers and thioethers are versatile building blocks in organic synthesis allowing various transformations including a number of C–C bond forming processes.

Wool-anchored Pd(OAc)2 complex: a highly active and reusable catalyst for desulfurative coupling reactions

A biomacromolecule-anchored palladium complex, wool-Pd(OAc)₂, was used as a catalyst for the Liebeskind–Srogl desulfurative coupling reactions of pyrimidin-yl thioether derivatives with terminal alkynes and arylboronic acids.

Cu-Catalyzed direct cyanation of terminal alkynes with AMBN or AIBN as the cyanation reagent

A Cu(ii)-catalyzed direct cyanation of terminal alkynes was reported with broad substrate generality in moderate to high yield.

Cu-Catalyzed direct cyanation of terminal alkynes with AMBN or AIBN as the cyanation reagent

A Cu(ii)-catalyzed direct cyanation of terminal alkynes was reported with broad substrate generality in moderate to high yield.