A gold(I)-catalyzed 6-endo-dig cyclization of aromatic 1,5-enyne was developed to synthesize 2-(naphthalen-2-yl)aniline. The functional group tolerance this examined systematically and a possible mechanism proposed. derivatization 2-(naphthalen-2-yl)aniline carried out facile access benzo[α]carbazole, benzo[c,h]cinnoline dibenzo[i]phenanthridine derivatives in divergent way.

The synthesis of chiral tetrahydrofurans and pyrrolidines starting from 1,2-diols or β-amino alcohols, respectively, by visible-light-mediated deoxygenation is described. Easily accessible monoallylated/propargylated substrates were activated either as inexpensive ethyl oxalates or as recyclable 3,5-bis(trifluoromethyl)benzoates to generate alkyl radicals suitable for 5-exo-trig/5-exo-dig cycli...

The importance of cyclopentanoid natural products continues to inspire the development of methods for the synthesis of 5-membered rings. For example, the Conia–ene reaction provides an atomeconomical synthesis of methylenecyclopentanes by the thermal cyclization of e-acetylenic carbonyl compounds. While the classic thermal reaction is limited to the exocyclic cyclization mode, group 6 metal com...

1,6-Enynes can be transformed into vinylidenecyclopentanes via gold-promoted 5-exo dig cyclisation followed by 1,5-hydride or -alkoxide shift.

The 1,6-annulated 2-pyridone motif is found in many biologically active compounds and its close relation to the indolizidine and quinolizidine alkaloid core makes it an attractive building block. A nickel-catalyzed C-H functionalization of 2-pyridones and subsequent cyclization affords 1,6-annulated 2-pyridones by selective intramolecular olefin hydroarylation. The switch between the exo- and e...

A chemo- and regioselective gold-catalyzed tandem 6-endo-dig cyclization/enyne cycloisomerization/1,2-migration process for the synthesis of decorated peptidomimetics is developed. Various migrating groups such as aryl, heteroaryl alkyl are tolerated in this method under mild conditions. This protocol successfully utilized to modify various oligopeptides, including substrates bearing drug amant...

An interesting silver(I)-catalyzed, one-pot intramolecular cyclization of epoxide-propargylic esters is described. A variety of 1,4-oxazine derivatives were obtained through a novel domino sequence, including three-membered ring-opening, 3,3-sigmatropic rearrangement, 6-exo-cycloisomerization and subsequent intramolecular elimination in moderate yields under mild conditions.

The mechanism and selectivity of a bicyclic hydantoin formation by selenium-induced cyclization are investigated. The proposed mechanism involves the intermediates formed by an electrophilic addition of the selenium reagent on a double bond of the starting 5-alkenylhydantoin prior the cyclization. These intermediates are readily converted into the more stable cyclic seleniranium cations. A key ...

Cp2Ti(TFA) is a broadly applicable catalyst for the [2+2] cycloaddition of bisenones by inner-sphere electron transfer. The attractiveness this mechanism shown comparison with outer-sphere ET methods. DFT calculations show that reaction proceeds through unique unfavorable 5-exo (the rate-determining step) and favorable 4-exo cyclization.