Abstract The regioselectivity of the intramolecular cyclization bifunctional α-phenyl alkenes can be controlled simply by choice organic chromophore as photocatalyst. central photoredox catalytic reaction in both cases is a nucleophilic addition hydroxy function to olefin substrates. N,N-(4-Diisobutylaminophenyl)phenothiazine catalyzes exo-trig cyclizations, whereas 1,7-dicyanoperylene-3,4,9,10...

This review summarizes recent progress in nickel-catalyzed arylative cyclizations of alkyne- and allene-tethered electrophiles using arylboron reagents, which are useful methods for the preparation diverse carbo- heterocyclic products. In many cases, nickel catalysis enables unique modes reactivity not readily available to other metal catalysts. The scope reactions is discussed detail, general ...

Glucopyranosylidene-spiro-1,4,2-oxathiazoles were prepared in high yields by NBS-mediated spiro-cyclization of the corresponding glucosyl-hydroximothioates. In an effort to synthesize analogous glucopyranosylidene-spiro-1,2,4-oxadiazolines, with a nitrogen atom instead of the sulphur, attempted cyclizations resulted in aromatization of the heterocycle with opening of the pyranosyl ring. Enzymat...

SnBr(4)-promoted oxonium-Prins cyclizations to form 2,3-disubstituted tetrahydrofurans (THFs) are reported. In the absence of an internal nucleophile, the carbocation intermediates are trapped by bromide to give 2,3-cis- and 2,3-trans-configured products; two variations with intramolecular trapping are also reported. One of these allows a single-step stereocontrolled synthesis of the core 2,3-c...

A new synthesis of 2-oxa-7-azaspiro[3.5]nonane is described. Spirocyclic oxetanes, including 2-oxa-6-azaspiro[3.3]heptane were converted into o-cycloalkylaminoacetanilides for oxidative cyclizations using Oxone® in formic acid. The expanded spirocyclic oxetane successfully gave the [1,2-a] ring-fused benzimidazole. X-ray crystal structure of the resultant new tetracyclic system, 1',2'-dihydro-4...

We report a unified strategy for the total syntheses of (-)-psychotriasine and (+)-pestalazine B based on the advanced intermediates of 3α-amino-hexahydropyrrolo[2,3-b]indole. To construct these structural motifs, a cascade reaction involving a BINOL-derived phosphoric anion-paired catalyst for enantioselective or diastereoselective azo-coupling/iminium-cyclizations was developed. The remaining...

The use of metal ions as templates in the synthesis of a range of macrocyclic Schiff base ligands varying in size (15-30 member atoms), in the number and nature of the potential donor atoms, and in flexibility is described. Factors controlling the course of the reactions are discussed. Open-chain intermediates have been isolated in several cases and mechanisms for the cyclizations are proposed....