Diphenylacetylene-Incorporating Octaphyrin: A Rigid Macrocycle with Readily Separable Conformational Isomers.

An expanded carbaporphyrinoid analogue, octaphyrin(2,1,1,1,2,1,1,1), containing two rigid diphenylacetylene moieties is reported. In contrast to traditional pyrrolic macrocycles where flexible conformers coexist in dynamic equilibrium, this macrocycle exists as two separable, conformationally stable stereoisomers, denoted as 1A and 1B. The conformational effect of both conformers, as well as their protonated forms, were thoroughly studied using NMR spectroscopy, UV/Vis, and single crystal X-ray diffraction analyses.

Resolution of Expanded Porphyrinoids: A Path to Persistent Chirality and Appealing Chiroptical Properties.

Chirality is a fundamental characteristic of nature. Expanded porphyrinoids and their analogues offer an attractive platform for delving into the intricacies of chirality. Expanded porphyrinoids comprise pyrrolic macrocycles and related heterocyclic systems.

Stereoselective Synthesis of Indolyl--glycosides Enabled by Sequential Aminopalladation and Heck Glycosylation of 2-Alkynylanilines with Glycals.

An efficient and general approach for the synthesis of indolyl--glycosides via aminopalladation and subsequent Heck-type glycosylation of easily available 2-alkynylanilines and glycals has been developed. This protocol features excellent stereoselectivity, a broad substrate scope, and mild reaction conditions. In addition, 2,3-pseudoglycals also successfully participated in this cascade reaction, affording C2/C3-branched indolyl glycosides with high regio-/stereoselectivity.

Palladium-Catalyzed Difunctionalization of Alkenes by Relay Coupling with Propargylic Pyridines: Synthesis of Indolizine and Indolizinone-Containing Bisheterocycles.

Palladium-catalyzed arylation/heteroarylation of aryl halide-tethered alkenes with propargylic pyridines has been established, which provides direct and efficient access to various oxindole, azaoxindole, dihydrobenzopyran, indole, and benzofuran-linked indolizines in good yields with a broad substrate scope and high functional group tolerance. This process enables the formation of one C-N and two C-C bonds in a single operation through an intramolecular carbopalladation and cycloisomerization sequence. Furthermore, an indolizinone-linked bisheterocyclic framework containing indole and benzofuran could be synthesized conveniently from tertiary propargylic alcohols involving methyl or phenyl migration.

Palladium-catalyzed -glycosylation and annulation of -alkynylanilines with 1-iodoglycals: convenient access to 3-indolyl--glycosides.

An efficient and practical approach for the synthesis of 3-indolyl-C-Δ1,2-glycosides through a palladium-catalyzed annulation/C-glycosylation sequence of o-alkynylanilines with 1-iodoglycals has been developed. This methodology has a wide scope of substrates and gives access to 3-indolyl-C-Δ1,2-glycosides in high yields. Furthermore, the product obtained here exhibits a high utility for further transformations.

Reagent-Controlled Divergent Synthesis of -Glycosides.

By turning on or switching off the directing effect of the C3-OH-located -diphenylphosphanylbenzoyl (-DPPB) group in glycals, a reagent-controlled protocol for divergent and regio- and stereoselective syntheses of -glycosides has been established. In particular, the silence of the directing effect of -DPPB was achieved by the introduction of a ZnCl additive, which is operationally simple and efficient. The flexibility of the novel protocol was exhibited not only by the easy access of both α- and β--glycosides but also by the versatility of the obtained formal Ferrier rearrangement products, which can be easily derivatized to various -glycoside analogues owing to the embedded multifunctionalities.

Palladium-Catalyzed Cross-Coupling of 2-Iodoglycals with -Tosylhydrazones: Access to 2-C-Branched Glycoconjugates and Oxadecalins.

A convenient and straightforward synthesis of diverse 2-C-alkenyl-glycosides through a palladium-catalyzed cross-coupling reaction between 2-iodoglycals and -tosylhydrazones has been developed. Further transformation of 2-C-branched sugars by Diels-Alder reactions provided oxadecalins in good yields